Houseboat prices vary immensely nationwide, says the marine agent Virginia Currer (01753 832312) who has Fighting Spirit (see article) on her books at pounds 36,000. "It's very difficult to quote a boat price. For example, I've got an ex-canal lighter in Islington for pounds 30,000 for a 10- year lease; a wooden ex-Admiralty picket boat on the tidal Thames at Isleworth for pounds 22,000; and a 93ft Dutch tjalk barge at Hoo in Kent for pounds 63,000."

It is possible to get a mortgage on a houseboat, though banks may take some convincing. But buying the boat is just the start. "People think they can live cheaply, particularly in the centre of London," says Virginia Currer. "But you need to consider residential mooring fees, which are likely to be around pounds 1,400 per year for a 50ft narrow boat. Then there's the cost of a British Waterways Residential Licence, and insurance, which will be pounds 500 or more a year. Some mooring fees will be much more expensive. For example, pounds 30,000 for the canal lighter in Islington might be within reach of many people, but on top of that the mooring fees are pounds 5.50 per month per foot. You also pay council tax."

Picking up a hulk for a song and doing it up is an option; but it's not likely to make a huge profit. "I have sold a 45ft narrow boat for pounds 7,500, but that needed a complete refit and was not on a residential mooring. If you buy a boat like that, you have to do the refit yourself otherwise it would cost more than the boat will ever be worth."

Most moorings are equipped with a hose point for water, mains electricity and phone lines. Gas and coal are often available from the local boat yards. "Once you have taken into account the domestic costs, it's no cheaper than living in a house," says Virginia Currer.

A proportion of her clients are young people who can't afford property, and also divorced people who have left the family home. "We get an incredible number of calls," says Currer, "but those who actually go ahead are a very small percentage. If people do have romantic notions, then I try to bring them down to earth immediately."