Derivative Financial Instruments - Schedule of Derivative Financial Instruments (Detail) - GBP (£) £ in Thousands |
3 Months Ended | 6 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|---|
Jun. 30, 2025 |
Jun. 30, 2024 |
Jun. 30, 2025 |
Jun. 30, 2024 |
Dec. 31, 2024 |
|
| Derivative Financial Instruments [Abstract] | |||||
| Opening Balance | £ 0 | £ 0 | £ 0 | ||
| Initial recognition on issuance of warrants | 4,439 | 0 | 0 | ||
| Losses on warrant remeasurement | £ 12,648 | £ 0 | 12,648 | £ 0 | 0 |
| Exercise of warrants | (14,483) | 0 | |||
| Closing Balance | £ 2,604 | £ 2,604 | £ 0 | ||