The society's move, aimed at those who want to buy a new home but feel they cannot afford the cost of moving, came as mixed evidence emerged on house prices.
Nationwide Building Society issued figures showing house prices that rose by 0.9 per cent in April. Its monthly survey, which also showed a 1 per cent increase for March, compares with figures from the Halifax two days ago which said house prices dropped by 0.3 per cent last month following a 0.3 per cent fall in March.
The Woolwich initiative has a £200,000 cap on the house sale price and a minimum new mortgage borrowing requirement of £25,000. Borrowers will have to take out a standard variable mortgage, currently at 8.4 per cent, with the society. They will also have to sell their house through its estate agency arm, which has 220 offices throughout the country.
Nationwide said variations with the Halifax's statistics were due to the fact its own lending focuses slightly more on the south of England. Dr Paul Sanderson, head of research at Nationwide, said: "Monthly changes need to be seen in the context of underlying trends and the key point is that both indices are saying the same thing - the trend is flat with continuing weaknesses in activity."