v3.25.2
Share Based Payments - Summary of Principal Assumptions used for Valuation of Share Options (Detail) - 2023 Share Options [member]
6 Months Ended
Jun. 30, 2025
GBP (£)
yr
shares
£ / shares
Grant Date June 20 2025 One [Member]  
Disclosure of terms and conditions of share-based payment arrangement [line items]  
Volatility 190.44%
Dividend yield 0.00%
Risk-free investment rate 3.91%
Fair value of option at grant date | £ £ 4.000
Fair value of share at grant date £ 0.004
Exercise price at date of grant £ 0.004
Lapse date Jun. 20, 2035
Expected option life (years) | yr 4.5
Number of options granted | shares 196,266,198
Grant Date June 20 2025 One [Member] | Vesting Dates One [member]  
Disclosure of terms and conditions of share-based payment arrangement [line items]  
Vesting dates Jun. 20, 2026
Grant Date June 20 2025 One [Member] | Vesting Dates Two [member]  
Disclosure of terms and conditions of share-based payment arrangement [line items]  
Vesting dates Jun. 20, 2027
Grant Date June 20 2025 One [Member] | Vesting Dates Three [member]  
Disclosure of terms and conditions of share-based payment arrangement [line items]  
Vesting dates Jun. 20, 2028
Grant Date June 20 2025 One [Member] | Vesting Dates Four [member]  
Disclosure of terms and conditions of share-based payment arrangement [line items]  
Vesting dates Jun. 20, 2029
Grant Date June 20 2025 Two [Member]  
Disclosure of terms and conditions of share-based payment arrangement [line items]  
Volatility 211.97%
Dividend yield 0.00%
Risk-free investment rate 3.84%
Fair value of option at grant date | £ £ 4.000
Fair value of share at grant date £ 0.004
Exercise price at date of grant £ 0.0004
Lapse date Jun. 20, 2035
Expected option life (years) | yr 3.5
Number of options granted | shares 1,108,027,715
Grant Date June 20 2025 Two [Member] | Vesting Dates One [member]  
Disclosure of terms and conditions of share-based payment arrangement [line items]  
Vesting dates Jun. 20, 2026
Grant Date June 20 2025 Two [Member] | Vesting Dates Two [member]  
Disclosure of terms and conditions of share-based payment arrangement [line items]  
Vesting dates Jun. 20, 2027
Grant Date June 20 2025 Two [Member] | Vesting Dates Three [member]  
Disclosure of terms and conditions of share-based payment arrangement [line items]  
Vesting dates Jun. 20, 2028
Grant Date June 20 2025 Two [Member] | Vesting Dates Four [member]  
Disclosure of terms and conditions of share-based payment arrangement [line items]  
Vesting dates Jun. 20, 2029
Grant Date June 20 2025 Three [Member]  
Disclosure of terms and conditions of share-based payment arrangement [line items]  
Volatility 253.88%
Dividend yield 0.00%
Risk-free investment rate 3.75%
Fair value of option at grant date | £ £ 4.000
Fair value of share at grant date £ 0.004
Exercise price at date of grant £ 0.0004
Lapse date Jun. 20, 2035
Expected option life (years) | yr 2
Number of options granted | shares 157,982,220
Grant Date June 20 2025 Three [Member] | Vesting Dates One [member]  
Disclosure of terms and conditions of share-based payment arrangement [line items]  
Vesting dates Jun. 20, 2026
Grant Date June 20 2025 Four [Member]  
Disclosure of terms and conditions of share-based payment arrangement [line items]  
Volatility 348.99%
Dividend yield 0.00%
Risk-free investment rate 3.62%
Fair value of option at grant date | £ £ 4.000
Fair value of share at grant date £ 0.004
Exercise price at date of grant £ 0.0004
Lapse date Jun. 20, 2035
Expected option life (years) | yr 1
Number of options granted | shares 1,304,702,251
Grant Date June 20 2025 Four [Member] | Vesting Dates One [member]  
Disclosure of terms and conditions of share-based payment arrangement [line items]  
Vesting dates Jun. 20, 2025
Grant Date June 20 2025 Five [Member]  
Disclosure of terms and conditions of share-based payment arrangement [line items]  
Volatility 253.88%
Dividend yield 0.00%
Risk-free investment rate 3.75%
Fair value of option at grant date | £ £ 4.000
Fair value of share at grant date £ 0.004
Exercise price at date of grant £ 0.004
Lapse date Jun. 20, 2035
Expected option life (years) | yr 2
Number of options granted | shares 711,098,349
Grant Date June 20 2025 Five [Member] | Vesting Dates One [member]  
Disclosure of terms and conditions of share-based payment arrangement [line items]  
Vesting dates Jun. 20, 2025