v3.19.1
Financial instruments - additional information - Credit risk (Details) - GBP (£)
£ in Millions
Dec. 31, 2018
Dec. 31, 2017
Credit risk    
Financial assets not past due or impaired due to renegotiation of terms £ 23 £ 22
Past due date but not impaired    
Credit risk    
Loans and receivables 27 23
Past due date but not impaired | Less than one year past due date    
Credit risk    
Loans and receivables £ 22 £ 17