Material accounting policies - Additional Information (Detail) - GBP (£) £ in Thousands |
6 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2025 |
Jun. 30, 2024 |
Dec. 31, 2024 |
Dec. 31, 2023 |
|
| Disclosure Of Summary Of Material Accounting Policies [Line Items] | ||||
| Accumulated deficit | £ (250,696) | £ (224,294) | ||
| Cash flows from (used in) operating activities | (7,595) | £ (7,060) | ||
| Cash and cash equivalents | 8,443 | 11,639 | 6,749 | £ 17,225 |
| Proceeds from issuing other equity instruments | 4,439 | £ 0 | £ 0 | |
| American Depository Receipts [Member] | ||||
| Disclosure Of Summary Of Material Accounting Policies [Line Items] | ||||
| Proceeds from issuing other equity instruments | £ 19,000 | |||