The Government this week announced it was nationalising Bradford & Bingley (B&B) after its share price had fallen 93 per cent to 20p by Friday evening and confidence in the bank had evaporated.

The former building society specialised primarily in buy-to-let mortgage deals. Money examines how landlords will be affected by the £50 billion rescue of the bank by the Treasury, and what will be the impact on the mortgage market?

Q: What kind of mortgages did Bradford & Bingley offer?

A: Bradford & Bingley was the biggest buy-to-let lender through its subsidiary Mortgage Express. It also offered self-certification mortgages, dubbed "liars loans" in some quarters because applicants did not need to provide proof of income. These two types of mortgages make up around 75 per cent of B&B's mortgage book. Mortgage Express has since closed for new business.

Q: Who is left in the buy-to-let market?

A: Birmingham Midshires, which is part of HBOS, is the UK's second biggest buy-to-let lender. Over the weekend, Birmingham Midshires ditched fixed-rate deals for buy-to-let lenders altogether. Mortgage Works, from Nationwide, is planning to raise rates and Chelthenham & Gloucester, owned by Lloyds TSB, will also increase rates on buy-to-let deals.

The best deal current available is from NatWest, at a rate of 6.44 per cent with a fee of £1,299, for up to 85 per cent of a property's value.

Q: What other changes have lenders been making?

A: Last year, deals were available for up to 90 per cent of a property's value, but the maximum available now is 85 per cent. Previously, some lenders allowed rental income to cover 100 per cent of mortgage repayments, but this is now back up to 125 per cent for most deals. This means that landlords expecting a rental income of £700 per month are only able to borrow £112,000 at a rate of 6 per cent, compared to £140,000 previously.

Q: How will this affect landlords?

A: As there are few new landlords entering the buy-to-let market at the moment, the closure of Mortgage Express is most damaging for existing landlords who are coming to the end of their deals. At the end of a fixed-rate period borrowers normally move on to a tracker rate. Landlords may find they will pay less by accepting this rate than remortgaging to another lender.

Q: What about customers with normal mortgages?

A: The same unfortunately applies to borrowers with traditional mortgages. B&B is likely to seek to reduce to exposure to the market, by raising mortgage rates to encourage customers to look elsewhere.

The worry for homeowners, particularly those who took out 100 per cent deals with B&B, is whether they will be able to switch to a deal with a rival lender. Lenders across the market have tightened lending criteria and raised the amount of equity that borrowers need to own in their homes.

Halifax, Britain's biggest lender which is being rescued by Lloyds TSB, is now lending up to only 75 per cent of a property's value in most cases. Borrowers could be forced to languish on B&B's standard variable rate, currently 7.14 per cent.