Share Based Payments - Summary of Principal Assumptions used for Valuation of Share Options (Detail) - 6 months ended Jun. 30, 2026 - 2023 Share Options [member]	GBP (£) yr shares £ / shares	GBP (£) yr shares $ / shares
Grant Date January 14 2026 One [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Volatility	260.56%	260.56%
Dividend yield	0.00%	0.00%
Risk-free investment rate	3.51%	3.51%
Fair value of option at grant date \| £	£ 0.4000	£ 0.4000
Fair value of share at grant date	£ 0.0005
Exercise price at date of grant	£ 0.0004
Lapse date	Jan. 14, 2036	Jan. 14, 2036
Expected option life (years) \| yr	1	1
Number of options granted \| shares	1,951,153,811	1,951,153,811
Grant Date January 14 2026 One [Member] \| Vesting Dates One [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Jan. 14, 2026	Jan. 14, 2026
Grant Date January 14 2026 Two [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Volatility	226.67%	226.67%
Dividend yield	0.00%	0.00%
Risk-free investment rate	3.53%	3.53%
Fair value of option at grant date \| £	£ 0.5000	£ 0.5000
Fair value of share at grant date	£ 0.0005
Exercise price at date of grant	£ 0.0004
Lapse date	Jan. 14, 2036	Jan. 14, 2036
Expected option life (years) \| yr	2	2
Number of options granted \| shares	174,109,121	174,109,121
Grant Date January 14 2026 Two [Member] \| Vesting Dates One [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Jan. 14, 2027	Jan. 14, 2027
Grant Date January 14 2026 Three [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Volatility	193.02%	193.02%
Dividend yield	0.00%	0.00%
Risk-free investment rate	3.67%	3.67%
Fair value of option at grant date \| £	£ 0.5000	£ 0.5000
Fair value of share at grant date \| $ / shares		£ 0.0005
Exercise price at date of grant \| $ / shares		£ 0.0004
Lapse date	Jan. 14, 2036	Jan. 14, 2036
Expected option life (years) \| yr	3.5	3.5
Number of options granted \| shares	1,324,308,581	1,324,308,581
Grant Date January 14 2026 Three [Member] \| Vesting Dates One [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Jan. 14, 2027	Jan. 14, 2027
Grant Date January 14 2026 Three [Member] \| Vesting Dates Two [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Jan. 14, 2028	Jan. 14, 2028
Grant Date January 14 2026 Three [Member] \| Vesting Dates Three [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Jan. 14, 2029	Jan. 14, 2029
Grant Date January 14 2026 Three [Member] \| Vesting Dates Four [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Jan. 14, 2030	Jan. 14, 2030
Grant Date January 14 2026 Four [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Volatility	226.67%	226.67%
Dividend yield	0.00%	0.00%
Risk-free investment rate	3.53%	3.53%
Fair value of option at grant date \| £	£ 0.5000	£ 0.5000
Fair value of share at grant date	£ 0.0005
Exercise price at date of grant	£ 0.0005
Lapse date	Jan. 14, 2036	Jan. 14, 2036
Expected option life (years) \| yr	2	2
Number of options granted \| shares	313,694,177	313,694,177
Grant Date January 14 2026 Four [Member] \| Vesting Dates One [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Jan. 14, 2026	Jan. 14, 2026
Grant Date January 14 2026 Five [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Volatility	175.64%	175.64%
Dividend yield	0.00%	0.00%
Risk-free investment rate	3.78%	3.78%
Fair value of option at grant date \| £	£ 0.5000	£ 0.5000
Fair value of share at grant date \| $ / shares		£ 0.0005
Exercise price at date of grant \| $ / shares		£ 0.0005
Lapse date	Jan. 14, 2036	Jan. 14, 2036
Expected option life (years) \| yr	4.5	4.5
Number of options granted \| shares	87,871,006	87,871,006
Grant Date January 14 2026 Five [Member] \| Vesting Dates One [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Jan. 14, 2027	Jan. 14, 2027
Grant Date January 14 2026 Five [Member] \| Vesting Dates Two [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Jan. 14, 2028	Jan. 14, 2028
Grant Date January 14 2026 Five [Member] \| Vesting Dates Three [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Jan. 14, 2029	Jan. 14, 2029
Grant Date January 14 2026 Five [Member] \| Vesting Dates Four [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Jan. 14, 2030	Jan. 14, 2030
Grant Date April 15 2026 One [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Volatility	256.68%	256.68%
Dividend yield	0.00%	0.00%
Risk-free investment rate	4.07%	4.07%
Fair value of option at grant date \| £	£ 0.2000	£ 0.2000
Fair value of share at grant date	£ 0.0003
Exercise price at date of grant	£ 0.0004
Lapse date	Apr. 15, 2036	Apr. 15, 2036
Expected option life (years) \| yr	1	1
Number of options granted \| shares	135,525,518	135,525,518
Grant Date April 15 2026 One [Member] \| Vesting Dates One [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Apr. 15, 2026	Apr. 15, 2026
Grant Date April 15 2026 Two [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Volatility	192.85%	192.85%
Dividend yield	0.00%	0.00%
Risk-free investment rate	4.16%	4.16%
Fair value of option at grant date \| £	£ 0.3000	£ 0.3000
Fair value of share at grant date \| $ / shares		£ 0.0003
Exercise price at date of grant \| $ / shares		£ 0.0004
Lapse date	Apr. 15, 2036	Apr. 15, 2036
Expected option life (years) \| yr	3.5	3.5
Number of options granted \| shares	134,170,264	134,170,264
Grant Date April 15 2026 Two [Member] \| Vesting Dates One [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Apr. 15, 2027	Apr. 15, 2027
Grant Date April 15 2026 Two [Member] \| Vesting Dates Two [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Apr. 15, 2028	Apr. 15, 2028
Grant Date April 15 2026 Two [Member] \| Vesting Dates Three [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Apr. 15, 2029	Apr. 15, 2029
Grant Date April 15 2026 Two [Member] \| Vesting Dates Four [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Apr. 15, 2030	Apr. 15, 2030

The expected volatility of the share price used to calculate the fair value of the share options granted. Expected volatility is a measure of the amount by which a price is expected to fluctuate during a period. The measure of volatility used in option pricing models is the annualised standard deviation of the continuously compounded rates of return on the share over a period of time.

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The option life of share options granted.

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The implied yield currently available on zero-coupon government issues of the country in whose currency the exercise price for share options granted is expressed, with a remaining term equal to the expected term of the option being valued (based on the option's remaining contractual life and taking into account the effects of expected early exercise). [Refer: Government [member]]

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Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table.

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The exercise price of share options granted.

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The percentage of an expected dividend used to calculate the fair value of share options granted.

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The number of share options granted in a share-based payment arrangement.

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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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The weighted average fair value of share options granted during the period at the measurement date. [Refer: Weighted average [member]]

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The weighted average share price used as input to the option pricing model to calculate the fair value of share options granted. [Refer: Option pricing model [member]; Weighted average [member]]

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Description of lapse date of share options granted.

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