Hundreds of homes poorly repaired by insurer-appointed builders.

The national Flood Advice Service has launched investigations into 100 cases of dodgy renovations by so-called cowboy builders appointed by insurance companies to repair homes ravaged by last summer’s floods.

It is investigating a further 200 cases of builders that have not been appointed by insurance companies.

Paul Hendy, flood adviser and consultant for Hull City Council and surrounding areas, said: “People are ending up with homes in worse shape than before the floods.”

Hendy said that while insurers used a list of approved builders for repairs, some of those builders were known to pass the job on to sub-contractors, which was where problems could arise.

He said: “Insurers may think they are dealing with competent builders, but really these homes are being left in the most horrendous shape you can imagine.”

At the end of March, housing minister Caroline Flint outlined plans to give local authorities greater control over rogue builders and impose serious penalties for illegal construction, including prison sentences of up to two years.

In the meantime, Hendy said: “The level of accountability is something that has to be addressed by the insurance industry as a whole.”

The ABI said: “The scale of the floods last year means builders are in short supply in areas affected. Our members are working hard to ensure repairs are carried out quickly and to a high standard. There were 180,000 claims from last summer’s floods and for the vast majority of work there was no such problem.”

Meanwhile, some homeowners in Hull and surrounding flood zones are constructing defences and barriers on their properties to reduce the excesses payable on their household policies after almost 100 people had their excesses increased to £10,000.