But pedigree dogs can bring heartache and expense because thoroughbred animals are more likely to suffer from hereditary conditions than mongrels. That can lead to large bills from the vet, so insurance premiums for a pedigree will cost more.

Fiona Pinkney at specialist insurer Petplan says: 'Pedigree dogs are more susceptible to illness than crossbreeds and insurance premiums reflect this.

'But given the likelihood that one in three will have an unexpected trip to the vet at some stage, pet insurance does give peace of mind.'

Figures from Petplan show that bloodhounds are at particularly high risk of eye and skin conditions. One in two insured by Petplan is the subject of a claim, closely followed by Great Danes, St Bernards and Shar-Peis, the favoured of Victoria and David Beckham.

Despite the dangers, Pinkney says that only 14 per cent of owners bother to insure, leaving themselves at risk of vets' bills that can spiral to thousands of pounds.

Rachel Collier, 26, from Stoke-on-Trent, Staffordshire, knows how costly a visit to the vet can be.

She has two Rottweilers, Beauty and Kara, and two German shepherds, Shadow and Saffron.

When Kara was a puppy, she suffered a leg injury that led to surgery costing £2,500. But luckily for Rachel, she had insurance.

'Kara was a lively puppy,' says Rachel, 'but she skidded on a polished floor and landed awkwardly, damaging a ligament in her leg.

To make things worse, she has arthritis in her knees, which can be common in Rottweilers. She had an operation and, thankfully, two years later she is doing well.' Rachel, who works for the local council, and husband Melvin, a bank worker, pay £110 a month to Petplan for budget cover for their four dogs.

The premium is steep, but Rachel believes it is worthwhile as the company insures for ongoing conditions, so Kara's arthritis will be covered for more than the 12 months some insurers set as a limit for paying out on a given condition.

Annual cover for a one-year-old male mongrel with Churchill Insurance would cost about £75 in Torquay, Devon. In contrast, cover for a oneyearold pedigree Irish red setter in the same area would cost £97.

However, Churchill covers a condition for only 12 months and the limit for any claim in one year is £3,000. More Than, which is owned by Royal & SunAlliance, operates in a different way.

Its annual premium for the same area would be £120 for a crossbreed and £132 for a pedigree, based on ownership of a Labrador. However, treatment continues until a dog has fully recovered, regardless of the time it takes, up to a maximum of £6,000 for each ailment.

Petplan would charge £142 for a crossbreed dog in Plymouth, Devon, and from £180 to £260 a year for a pedigree in the same area, depending on breed.

Conditions are covered for life, though the maximum claim is £4,000 in any one year and premiums will probably rise if a claim is made.