Norwich's two MPs last night joined forces to call for a national inquiry into contractors Connaught in the hope it could find answers about its disastrous collapse which cost more than 300 people in Norwich their jobs.

Chloe Smith and Simon Wright, MPs for Norwich North and South respectively, have jointly written to business ministers Mark Prisk and Ed Davey calling for the inquiry into the conduct of the directors of Connaught Partnerships.

Jobs went in Norwich last month when Connaught Partnerships, which had a �17.5m contract with City Hall to maintain and fix some 17,000 council homes, went into administration.

The city council has defended the signing of that contract earlier this year despite concerns Connaught's bid was 'abnormally low' and at least �5m lower than the amount the next lowest bidder said would have to be spent to deliver the contract.

Miss Smith and Mr Wright have called for a local, independent inquiry into the city council's contract with the failed firm, calls which the city council has rejected.

The council has insisted it followed proper procurement rules and it is understood the Audit Commission, which as part of its annual report into the city council has been looking into the authority's procurement processes, including the award of the Connaught contract, raised no concerns.

But the spotlight has also fallen on Connaught at a national level, with the government understood to be considering an investigation into the conduct of its directors.

The city's MPs want to meet ministers to raise 'all aspects', both in Norwich and nationally, of what Ms Smith described as 'a sorry saga'.

Their letter backed a national probe into Connaught, saying: 'We believe this is justified and it would contribute to resolving the current crisis for our local council, as they endeavour to analyse the situation and re-let one of Connaught's largest contracts.'

The two MPs said they were offering constructive help to the city council but Miss Smith said: 'Most people want to see an independent inquiry into just how the city council has got into this position.

'I think there should be a local look – not behind closed doors at the council – at who knew what, when, within Norwich City Council about Connaught throughout this disaster.

'In other words, how could the city have fallen for Connaught?'

Alan Waters, cabinet member and chair of the council's contracts working party, said: 'We are delighted the city's MPs are calling for a national inquiry into the collapse of Connaught as it was not the contracts we negotiated that failed, but the national company.

'When we signed the contracts, we were doing so with a FTSE250 company that was the biggest provider of housing services in the country, well regarded by the City, and to which auditors and credit rating agencies gave a clean bill of health.

'The FSA is already conducting an inquiry into Connaught and there are clearly questions that need to be answered - not just for us but for the other 150 councils and housing associations which were affected by its collapse.

'If a national inquiry reveals anything we need to look at, then of course we will. But we will not be spending taxpayers' money on a local inquiry because this is not where it went wrong.'

Mr Wright said: 'The impact on Norwich of the Connaught collapse has been dreadful. A national inquiry will also help establish whether the company behaved appropriately in its dealings with local councils.

'While I accept that the council wants to move on, it's vital that we reflect on why we're in this dreadful position and whether it could have been avoided.'

The city council had hoped to transfer the contract to another company on the same terms and conditions as Connaught but lawyers advised them not to because the authority could face a legal challenge.