The trust is considering its social responsibilities for housing

It says many of its staff and other people working in the countryside cannot afford to live there due to soaring house prices and rents.

Most of its 5,000 houses and cottages are let privately, the others are used by staff or as holiday homes.

The trusts owns residences in more than 40 villages in England, Wales and Northern Ireland.

Historically many houses have been acquired as part of larger rural estates, often providing dwellings to house workers and local service providers.

We do want to let to local people where possible and give them the most opportunity Claire Sharrett, National Trust

However the trust has been moved to review its policy as the opportunities farms and estates provide for employment and housing have declined and affluent migrants from towns and cities have moved in.

Claire Sharrett, from the trust, said: "People working in towns and cities wanting to leave has seen house prices shoot up in rural areas.

"We're looking at all these different factors and at this point in time it is just a discussion paper not a statement of policy so there will be no radical changes to our tenancy agreement.

"But we do want to let to local people where possible and give them the most opportunity."

The results of a consultation with staff and current tenants are due in the autumn.