FACTBOX - Buy-to-let property market

LONDON (Reuters) - The nationalisation and sale of Bradford & Bingley, Britain's biggest lender to people buying homes to rent them out, has raised questions about the health of the buy-to-let sector.

Analysts said on Monday the move could exacerbate the UK housing market downturn by restricting loan finance for buy-to-let landlords, forcing some to put their investment properties on the market.

Here are some key facts about Britain's buy-to-let market.

- There were 1.1 million outstanding buy-to-let mortgages at the end of June this year, with a combined value of 132.5 billion pounds. That is equivalent to 10.9 percent of all residential loans.

- Bradford & Bingley, operating under the Mortgage Express brand, was the leading buy-to-let loan provider in terms of outstanding balances, followed by HBOS unit Birmingham Midshires, Paragon, Bank of Ireland's Bristol & West, and Cheltenham & Gloucester, a subsidiary of Lloyds TSB.

- Buy-to-let investments became increasingly popular in the mid-1990s as the property market began to emerge from its late 1980s crash, and grew strongly in the current decade. At the end of 2000, there were just 120,300 buy-to-let loans outstanding, accounting for 2 percent of total mortgages.

- Buy-to-let investors have so far kept up a better-than-average repayment record. At the end of June, 1.10 percent of buy-to-let mortgages were more than three months in arrears, less than the 1.33 percent arrears level for the mortgage market as a whole.

- Most British buy-to-let investors are affluent people in their forties.

Sources: Council of Mortgage Lenders, Association of Residential Letting Agents.

(Reporting by Myles Neligan; additional reporting by Rhys Jones in London)