The government says that its Help to Buy scheme will assist people trying to get on the housing ladder who can afford mortgage repayments but are struggling to raise a deposit.

But critics say that the government guarantee, that forms part of the second phase of the scheme, could create a housing bubble in the UK.

Not all mortgage seekers will be able to sign up, and those who do will still have to go through "rigorous" affordability checks by their lender.

Haven't I heard about this for a while?

Yes, in fact some parts of the scheme have been operating for a few months.

The first phase started in April in England. This sees the government offering a 20% equity loan to buyers of newly-built properties. These buyers must offer a 5% deposit.

Similar schemes operate in Wales and Scotland - all of which are aimed at encouraging housebuilding.

But that's not all, is it?

No, the second phase of the scheme, originally planned for January 2014, has been brought forward so mortgage products are available from now.

Under this system, borrowers across the UK can put down a deposit of as little as 5% of the property price. The lender offers a mortgage covering the other 95%.

Lenders can sign up to the Help to Buy scheme and pay a fee to the government, which will provide a seven-year taxpayer guarantee covering 15% of the loan value. That guarantee can be called in if the borrower defaults.

It is available for properties sold for up to £600,000 in the UK. The scheme is expected to continue for three years.

Are the lenders keen?

There has been a mixed response so far.

RBS and Lloyds Banking Group - both of which are taxpayer backed - are participating in the second phase of Help to Buy.

Smaller lenders Virgin Money and Aldermore have announced that they will be involved as well, from January.

Barclays and Santander have also said they would join, but have yet to give details. Nationwide Building Society have yet to decide.

How much do these mortgages cost?

A few lenders have started to reveal the pricing of these 95% mortgages.

RBS and NatWest are offering a two-year, fixed-rate mortgage starting at 4.99% for those with a 5% deposit, with no fee.

Halifax will be taking applications in a few days at a rate of 5.19% with a £995 fee for those with the same deposit.

That is relatively competitive compared with prices outside of Help to Buy, although borrowers are likely to get a better deal if they save up longer for a deposit. These 95% mortgages have all but disappeared from the market since the start of the financial crisis