Adam Golder, of RK Harrison Insurance Brokers, says: "Dukes and duchesses aside, 90 per cent of people with high-value homes have probably got inappropriate cover. This is especially likely in the mid-wealthy range of, say, pounds 300,000 to pounds 700,000 worth of valuables. Even those with houses and collections in the millions can make huge savings by being better advised."
Nick Harvey of Gauntlet Heritage, another firm that specialises in stately homes and art collections, says: "The service the specialist brokers provide is nothing more intrinsically complicated than showing people how to cover their own particular risks properly. Although a succession of well-known companies have leapt into the 'high net worth' market, many of them have a flawed understanding of what is involved.
"For example, people may assume that a valuable painting is a higher risk than, say, a television set. But the truth is that most burglaries are for petty items. Statistics will show you that, pound for pound, a television or a video is much more likely to 'walk' than an Old Master. It will come as a surprise to some people that the correct charge rate for fine art inside a London house is only around a third to a half that of general contents. However, you need to find the specialist insurers that offer the rate, or you could waste an awful lot of unnecessary money elsewhere."
To emphasise the point, Mr Harvey quoted the case of a woman in a smart Chelsea flat containing several million pounds worth of assorted works of art. "It was gratifying to be able to reduce her costs by well over 50 per cent," he says. "It is all because the specialists categorise different assets in different ways rather than lumping them all together at a 'standard' rate."
Seeking out specialist insurers direct can be quite time-consuming, but the specialist broker will cut a lot of the red tape by being able to assess exactly what is required on the client's behalf. If word of mouth does not suggest a suitable broker's name, auction houses such as Sotheby's or Christie's can usually provide recommendations. While premium savings are very welcome, promptness of payout after a theft - or other disaster, such as a flood or fire - is important, too.
RK Harrison's Mr Golder says: "On 5 November last year [the highest risk individual day of the year for burglary, by the way] the Earl of Pembroke had a famous painting, Rembrandt's Mother, stolen from Wilton House. I dare say he was none too pleased at that, but because we had set up his cover through the right company and in the right way, he had a very substantial cheque in his hands in seven days."
Although quotations will always need to be on an individual basis, the following gives some guidelines.
The quotation for a house in London SW3 (Chelsea/Knightsbridge) worth pounds 1,000,000, with contents valued at pounds 300,000 - of which pounds 200,000 is antiques, furniture, jewellery and so on - would be pounds 5,677 - including pounds 50 excess - with a well-known composite insurer. The premium quoted by a specialist insurer identified by broker - no excess - would be pounds 2,920.
Gauntlet Heritage can be contacted on 0171-490 4163, and RK Harrison on 0171-423 4400.