Fresh fears have been raised that Covid restrictions could go on beyond June after furlough was extended to the end of September.
The Job Retention Scheme will pay 80% of workers' wages until September 30, with firms expected to contribute more from July.
That is despite the fact Chancellor Rishi Sunak said Budget support - announced at 12.30pm today - would "align" with the roadmap.
Boris Johnson's path out of lockdown restrictions says all legal restrictions could be lifted from June 21 at the earliest.
But the Prime Minister has made clear that is the earliest possible date and could be pushed back if England fails four key tests.
Those include the emergence of a concerning variant like the P.1 Brazil strain, six cases of which have been found in the UK.
Government sources told the Mirror the support package needed to have an "imperfect relationship" with the roadmap because so much was unknown.
And speaking to Playbook, sources admitted the Chancellor needs to "provide a cushion" in case something goes wrong.
Tory minister Simon Clarke today said it was important to have "an element of flex" in case "there is any slippage" in the roadmap.
He said things may go better than planned with the virus, but there had to a "margin" in case they do not.
The minister in the housing department told Sky News: "I think we all absolutely hope and intend to be having a very normal summer and that is what the roadmap steps out, a series of staged steps.
"But we’ve always been clear that there is a degree whereby we don’t have full control of events, do we - if the virus takes an extra twist, if for any reason things change beyond what the roadmap sets out.
"Clearly if anything one hopes things may go even better than planned."
Around 4.7 million people were furloughed at the end of January, where the Government pays 80% of an employee’s wages.
Employers will be asked to start contributing 10% to the scheme in July, and 20% in August and September as the economy reopens after lockdown.
It means furlough will have been running for an astonishing 18 months.
Meanwhile fourth grant from the Self-Employment Income Support Scheme (SEISS) will be available to claim from April, worth 80% of three months' average trading profits up to £7,500.
And while details are still to be confirmed, the Treasury say "many" people who became newly self-employed in 2019-20 will be eligible for support for the first time.
The Chancellor is set to make cash grants available to more than 600,000 extra people who didn't qualify before, it's suggested.
But there are questions about the figure, which is thought to be anyone who submitted a 2019/20 tax return but hasn't previously claimed. There are several barriers to claiming the scheme, not just being newly self-employed.
