John Axford, an Oriental ceramics specialist, director of the Salisbury auctioneer Woolley and Wallis and an Antiques Roadshow expert, found a pleasant surprise in a house in the New Forest which had been burgled. There to help assess the value of stolen items for an insurance claim, he saw a small mug on the fridge.
He said: "This totally unrecognised and ignored thing was a very rare piece of Japanese porcelain, a 1670 Kakiemon tankard bought by the owner's mother at a house sale in the 1940s." Only three other mugs have been recorded. This one was sold in May 2001 to the Ashmolean Museum, Oxford, for £21,000.
Mr Axford also still cherishes a photograph of two Chinese vases covered with grime, part of a large and valuable collection which had largely gone undusted for years by its elderly owner who had since died. Although not in the same league as the Japanese mug - they sold for only £1,000 apiece - the vases are an extreme example of how objects may be undervalued, and underinsured.
Even if you do not have any priceless oriental porcelain, you may have art items whose value is not fully appreciated.
Zurich Insurance's client manager, Kris Coombes, says: "If you have had no valuation in the past 10 years, you may not have sufficient cover." The value of art and antiques has mushroomed in the past decade. Anyone who bought items years ago, or has inherited them, may not have an up-to-date valuation.
Mr Coombes cites the example of a client with four paintings by the early 20th- century Newlyn artist, Dorothea Sharp. Valued in 1988 at £16,000 in total, and not separately specified on the client's insurance policy, three were revalued recently at £25,000 and one at £50,000. Another collector who bought two paintings by the late 19th-century marine artist, John Steven Dews, for under £2,000 recently found they were worth more than £20,000 each.
Bonham's valuations director, Paul Davidson, says the work of British artists such as Patrick Heron and LS Lowry, as well as Mary Fedden, Winifred Nicholson, Helen Bradley, Mary Potter and Sheila Fell, have appreciated dramatically. Artists' work can also appreciate overnight when they die.
In the ceramics field, even broken items can be valuable, Mr Axford says. He sold for £2,300 the pieces of a vase which had been smashed in the 1995 Kobe earthquake, and he has a 1680 Chinese bowl which has been broken in two and repaired. It is expected to make £6,000 at auction.
If you have art items of significant value, how you insure them will depend on their value. With home contents valued at £80,000 to £90,000, a standard off-the-peg policy should be sufficient, says Steven Hill, a Cardiff-based valuer and chief executive of the National Association of Valuers and Auctioneers. Above that, or with buildings worth £300,000 to £400,000, you should consider a high-net-worth (HNW) policy. This will cover house and contents, and probably your motor, yacht and travel needs. Major art collectors whose cover needs are quoted in millions require bespoke cover through a Lloyd's syndicate.
There are a dozen HNW policies on the market. They claim to offer greater flexibility and a more personal service than is available with a standard policy.
Premiums will depend on several factors: apart from the sums to be insured, the age and occupation of the householders (retired people whose house is occupied during the day present less risk), claims history, the security of the property, its age, who lives there (it will cost more to insure a house where one wing is let as holiday self-catering accommodation), and whether there is other business use.
It is hard to compare policies purely on price, because they differ in the cover and the level of service. Oak Underwriting gives the phone number of the managing director, Anthony Lumsden-Cook, to clients, and once put a policyholder up in the Ritz Hotel when his swimming pool overflowed in Belgravia, central London.
The higher cost of the Zurich policy is due to it employing its own valuers. The quotation from AA insurance brokers uses two separate policies for buildings and contents. This can cause problems with a claim if the two insurers disagree about the payout. Most insurers will accept payment by regular direct debit, but some charge for it.
There are several ways to keep premiums down, James Cole, AA Select's customer service manager, says. Clients should keep an inventory file with receipts or other proof of ownership and should improve security. Door and window locks, an approved alarm system and smoke alarms may be a policy stipulation. With high-value small items, particularly silver and jewellery, the company may require a safe installed.
Points must be checked with a HNW policy. It will have an overall limit for valuables, within which there will be a single- item limit, which may be as low as £5,000 or as high as £15,000. The standard excess is usually higher than with a standard policy. Check that the policy pays full replacement value.
If items are likely to leave the house, check they are still covered under what is known as an all-risks clause. You may need cover for a sculpture in your garden, or against pet damage if you have a boisterous dog. Of particular relevance to art items are new acquisition cover and an automatic increase in cover in the event of the artist's death.
Above all, a recent valuation is important and, as all the experts we spoke to emphasised, it should be accompanied by photographs or even videos of the items in situ and from different angles. "There is an 80 per cent better chance of recovering stolen items if they are photographed," Steven Hill says.
FINDING A VALUER
You can approach an independent valuer or an auction house. The insurance company may have its own valuer, or may suggest names from its regular experts. You can get a rough idea through internet research, and most valuers will give an indication of value over the phone if you know the name of the artist.
How much? Not cheap. Expect £90 to £100 for each hour on the premises, £350 to £500 for a half-day or £700 to £800 for a day. Some insurers offer a special deal on valuation terms. Oak Underwriting builds in a seven-year annual revaluation contract and will spread the cost along with the premiums by monthly direct debit.
What do they do? A valuer will produce an inventory with descriptions and photos of valuables. Make sure you know what the end report will look like, Also, make sure both parties know which items are to be valued, the whole house, or just the art and silver? A proper valuation is worthwhile.
But remember ... Valuers are not licensed. Some may be dealers as well, which means they hope to get you to sell and have an interest in hyping the value of your possessions. Choose one by recommendation or from your insurer's list. Avoid adverts in the Yellow Pages that say "Best prices paid".
The following are professional associations of valuers which can give you names of local firms:
* National Association of Valuers and Auctioneers 02920 227787 www.nava.org.uk
* Society of Fine Art Auctioneers 01483 225891 www.sofaa.org
* Royal Institute of Chartered Surveyors (Fine Art Faculty)
0207 222 7000 ext 494 www.rics.org.uk/afa