The pound is now trading at 1.307, down nearly 2.5 percent so far this week, the worst since its 4.1 percent weekly decline in 2016 in the aftermath of the Brexit referendum.
And bookies have slashed the odds on the Prime Minister stepping down, with Paddy Power saying it had cut the odds on her stepping down this month by half overnight.
He acknowledged, however, that they could not force the Prime Minister's hand and that it was up to her to decide whether she wanted to carry on.
Backbencher Mark Pritchard suggested a "small number" of colleagues were raising questions over her leadership in text message exchanges and warned them "there is no vacancy at Number 10".
In a round of broadcast interviews, Shapps said the experience from Gordon Brown and John Major's premierships, was that leaders in May's position rarely recovered.
Veteran backbencher Michael Fabricant said of Shapps: "I wouldn't buy a used auto from one embittered colleague - let alone take advice from him about who should be PM".
Mr Shapps said support for a leadership election was growing, with some current Cabinet ministers privately signalling their support.
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More than 50 people have been confirmed dead and 200 injured in the shooting, making it the deadliest in United States history. This latest shooting appears to be the case again as U.S. authorities have ruled out the group's involvement.
He said the group of MPs supporting him included members across policy divides and covered Brexiters and those who supported remaining in the European Union (EU).
"One of the things that established itself very clearly was that the view of the party - of both parliamentary colleagues and activists - is that they regard, correctly, the responsibility of the Conservative Party to be effective and cool-headed in government".
Those aged 18-34 think Mrs May fighting the next election as party leader would bad for the Conservatives by 54% to 16%, while those aged 55 and over think it would be good by 45% to 30%.
Most MPs Sky News contacted said Mrs May should stay on for the good of party and country, praising her "grit" after a problem-plagued conference speech.
Business minister Margot James has claimed the plot to oust May was being led by "some ex-Cabinet ministers or ex-ministers who are extremely embittered individuals who just want to get their own back on the fact that they don't feel recognised".
The key announcement was her long-promised cap on energy bills, the Prime Minister announcing that a draft bill would be passed next week to "end rip-off energy prices once and for all".