v3.25.0.1
Material accounting policies - Going concern (Details)
£ in Thousands, $ in Millions
12 Months Ended
Jan. 24, 2025
USD ($)
Dec. 31, 2024
GBP (£)
Mar. 11, 2025
GBP (£)
Mar. 06, 2025
GBP (£)
Dec. 31, 2024
USD ($)
Dec. 20, 2024
USD ($)
Sep. 30, 2024
GBP (£)
Jun. 30, 2024
GBP (£)
Dec. 31, 2023
GBP (£)
Dec. 31, 2022
GBP (£)
Dec. 31, 2021
GBP (£)
Significant accounting policies                      
Cash and cash equivalents   £ 22,556         £ 42,806 £ 66,786 £ 48,680 £ 62,927 £ 212,660
Net shareholders' deficit   (499,341)         (55,328) (42,081) (49,779) 7,318 61,561
Cash and cash equivalents on hand   22,556         £ 42,806 £ 66,786 £ 48,680 £ 62,927 £ 212,660
Proceeds from issuing shares   15,629                  
Mudrick capital                      
Significant accounting policies                      
Non-contingent capital commitments | $           $ 25          
Backstop capital commitments | $           25          
Maximum | Mudrick capital                      
Significant accounting policies                      
Capital commitments receivable | $           $ 50          
Liquidity position at the date of signing of the report                      
Significant accounting policies                      
Cash and cash equivalents   22,500 £ 77,000 £ 77,000              
Net shareholders' deficit   (492,000)                  
Cash and cash equivalents on hand   £ 22,500 £ 77,000 77,000              
Expected net cash outflows from operations over next 12-month period       £ 100,000              
Convertible senior secured notes                      
Significant accounting policies                      
Mandatory cash balance under loan covenants | $         $ 10            
Underwritten public offering | Share transaction                      
Significant accounting policies                      
Proceeds from issuing shares | $ $ 90                    
Underwritten public offering | Share transaction | Mudrick capital                      
Significant accounting policies                      
Proceeds from issuing shares | $ $ 25