sentences:  It was noted that at the budgeted cost of £284.4m, the cost-benefit ratio of the project was only 0.4, so funding a cost overrun now estimated at £73.4m on top of the £49.2m Transport for London were already contributing, would not give value for money.It stated that Transport for London's sunk expenditure on the project was £71.2m, of which £15.5m was for buying an additional train, which has been delivered and put into service.In 2018, the government offered Transport for London the £73.4m additional funding it was apparently asking for, taking total funding available to £357.8m, subject to Transport for London accepting cost overrun risk again.