v3.26.1
Trade and other receivables (Details) - USD ($)
$ in Millions
 6 Months Ended 12 Months Ended
Jan. 01, 2025
Jun. 30, 2026
Dec. 31, 2024
Dec. 31, 2025
Trade and other non-current receivables [abstract]        
Accrued revenue and lease incentive   $ 1.3   $ 2.0
Payment in advance for property, plant and equipment   20.9   22.2
Deferred consideration   96.2   89.3
Withholding tax receivables   26.5   22.3
Other receivables   7.0    
Trade and other non-current receivables   151.9   135.8
Trade and other current receivables [abstract]        
Net trade receivables   109.1   107.5
Other receivables   35.2   33.4
Prepaid land rent   1.5   2.1
Other prepaid expenses   6.5   9.2
Advance payments   32.2   12.4
Withholding tax receivables   3.6   10.1
VAT receivables   8.0   6.7
Trade and other current receivables   196.1   181.4
Accrued revenue   $ 33.0   45.2
Cash flow projection period for assessment of withholding tax asset recoverability   5 years    
Vendor loan notes issued on disposal of subsidiaries | Rwanda, Rwanda Francs        
Trade and other current receivables [abstract]        
Notional amount   $ 70.0    
Interest rate   12.00%    
Repayable term   2 years    
Vendor loan notes issued on disposal of subsidiaries | United States of America, Dollars        
Trade and other current receivables [abstract]        
Notional amount   $ 24.5    
Repayable term   3 years    
NIGERIA        
Trade and other current receivables [abstract]        
Withholding tax rate on colocation and telecommunication tower services 2.00%   10.00%  
Maximum        
Trade and other current receivables [abstract]        
Non-current receivable due term   20 years    
Cost        
Trade and other current receivables [abstract]        
Net trade receivables   $ 124.6   119.6
Allowance for expected credit losses        
Trade and other current receivables [abstract]        
Net trade receivables   $ (15.5)   $ (12.1)