Analysis by Moody's, the financial services giant, has added to the growing chorus of concern over Transport for London's (TfL) financial situation.
Moody's Public Sector Europe echoed earlier analysis suggesting that the fiscal impact of the Crossrail delay will be 'significant over the medium term'.
TfL is facing budgetary pressures including the loss of its general operating grant, a freeze on fare increases and reduced passenger numbers in London.
In recent weeks transport secretary Chris Grayling and London politicians have all commented on what has been called the 'perilous' financial situation the authority faces.
The report states: 'TfL is currently generating a net operating deficit (including capital renewals and financing costs), because of the reduction in grant revenue, the ramp up of its cost cutting programme and the staged opening of the Elizabeth line. The deficit was forecast to be around £677m in fiscal 20181, and is projected to increase to £968m in fiscal 2019.
'TfL plans to cut annual operating costs by £1.2bn by fiscal 2023. Although it had initially expected to return to an operating surplus in fiscal 2022 as a result of the cost cutting programme, this date will now likely be pushed forward because of costs associated with the Crossrail delay.'
Moody's estimated the impact of the Crossrail delay on planned passenger revenue and suggested there will be a shortfall of around £200m in fiscal 2020, in line with recent estimates published by the London Assembly, and a shortfall of £400m in fiscal 2021.'
It also found that TfL 'is now more reliant on its operational performance to fund its activities than in the past as the revenue it receives through grants has declined to 18% of total operating income in fiscal year 2018 from 29% in fiscal year 2014'.
'Crossrail's delayed opening is one of a number of budgetary challenges that Transport for London is facing,' said Zoe Jankel, a Moody's vice president -- senior analyst and co-author of the report.
'We expect that the most significant impact of the Crossrail delay will be in the 2021 fiscal year, with a revenue shortfall of around £400m and a loss of operating surplus.
'Overall, we expect that TfL will be able to manage the impact of the delay using its available resources and spending flexibility. However, this will weaken its ability to cope with any other unforeseen costs or revenue shortfalls.'
Moody's stated that the fare freeze, introduced by London Mayor Sadiq Khan in 2016, affects around 50% of TfL's passenger income and will remain in place until 2020. TfL's passenger numbers, a leading indicator of the health of London's economy, fell by 1% in fiscal 2018 on an annual basis.
Despite the delay, Crossrail remains critical for TfL, with the new line boosting the capacity of London's railway network by 10% and bringing an additional 1.5 million people to within 45 minutes of central London.
The Elizabeth Line as it will be called is likely to contribute 14% of TfL's passenger revenue by 2023 and 12% of its total operating revenue.