She told delegates at Harrogate's International Centre that a Tory insider surprisingly saw winning a majority in parliament as a “nightmare” - as now the burden is all on them to deliver on their promises.
Ridge said: "A Tory source told me yesterday that in some ways a majority Conservative government is a nightmare.
“He hasn’t got the Lib Dems to blame if he can’t deliver.”
She added: "The manifesto was more like a wishlist. They promised a budget surplus, but they also promised £8bn for NHS and cuts to inheritance tax.
“Where is all this money going to magically come from?
“If these guys are going to stick to their manifesto promises on huge tax cuts the squeeze is going to come from somewhere.”
Ridge speculated whether the Tories will make cuts sooner rather than later since they are secure in government for the next five years.
She said: “On the political side it’s better to get the cuts out of the way quickly.
"People forget about it five years later when you go into an election."