Labour could be on course to one of the largest majorities in history and remain in power for “a very long time indeed”, Cabinet ministers have acknowledged.
Chancellor Jeremy Hunt said Sir Keir Starmer could extend the franchise to under-16s and EU citizens to entrench Labour in power.
Work and Pensions Secretary Mel Stride said opinion polls indicated Labour was heading towards “the largest majority virtually in the history of this country”.
And Welsh Secretary David Davies said the polls were pointing to a “large Labour majority”.
The comments are further signs that the Tories are now focused on saving as many MPs as possible to form a credible opposition to Sir Keir.
The Conservatives have warned would-be Reform UK supporters not to split the centre-right vote because Labour could benefit.
Mr Hunt said: “I think when people go to the polls, they will reflect on the dangers of Labour having such a big majority and then changing the rules by giving votes to people at the age of 16, giving votes to EU citizens, so that they’re here not just for a short time, for a very long time indeed.
“Compared to that, they will look at a Conservative government that hasn’t got everything right but took difficult decisions having inherited an economy that had higher inflation than nearly any of our major competitors.
“It is now lower, not just lower inflation but lower taxes, and soon hopefully lower mortgages as well.”
The Labour manifesto commits to lowering the voting age to 16 but does not include a policy of allowing EU citizens to take part in general elections.
Meanwhile Work and Pensions Secretary Mel Stride suggested voters should think about “what kind of opposition you’re going to get”.
Asked about recent comments by Defence Secretary Grant Shapps that a Conservative victory is “not the most likely outcome”, Mr Stride told BBC Radio 4’s Today programme: “Where Grant is absolutely right is that the polls have been stuck broadly in the same position for some time now.
“That shows us a long way behind Labour and, indeed, if you take those polls and extrapolate that into a result, you could end up seeing a Labour government with 450 or 460 seats, the largest majority virtually in the history of this country.
“And I think the question that Grant is servicing, which I think is a perfectly sensible question to ask, is that if that is where it goes – if the polls are right, and they stick where they are through to election day and that is the result – it is to some degree about what government colour you get, but it is also substantially about what kind of opposition you’re going to get.
“And whether you’re going to have a Parliament that is able to actually hold government to account or not.”
Mr Stride added: “I don’t think we should assume that the polls are the same as the only poll that’s going to matter is what happens on General Election day.”
Mr Davies told The Sun the polls “never get it 100% right” but “they’re clearly pointing at a large Labour majority”.
He said: “I don’t know how large that will be, but you know, I’m not stupid either.
“At the same time … I don’t detect any great enthusiasm for the Labour Party either.
“So I’m not absolutely certain that that people know exactly what’s going to happen in the election.
“But I do agree it points in one direction only.”