Lloyd's insurers are braced for their biggest profits decline since Hurricane Katrina hit in 2002.

After two years of low insurance claims, underwriters have been hit by a flurry of big claims from around the world, with events ranging from record tornado damage in the US to floods in Mississippi and Australia and a major hotel fire in Las Vegas.

While there was no one giant event, the high number of one-offs with damage tolls of $500 million to $1 billion have been piling up.

Nick Johnson, analyst at stockbroker Numis, said: "It's definitely going to be a tough halfyear for some underwriters. But it's guesswork as to who will be hit and who won't. It's not like Katrina, when everyone got whacked."

Catlin, Chaucer, Amlin and Hiscox are among big Lloyd's underwriters quoted on the Stock Exchange.

But Johnson added that all insurers will have been hit by the poor investment environment. Bad returns on gilts, equities and cash mean their profits from investing premium income will be badly down.

US insurance giants like AIG, Travelers and Allstate are expected to report terrible second-quarter profits when the results season starts next week.

"We're going to see amazingly bad numbers from the property insurers," Meyer Shields, analyst at Stifel Nicolaus said.