Portsmouth City Council had to cobble together cash for better materials after it was told the planned surface was not good enough.

The problem came to light during a site visit by representatives from the British Cycling Federation, the sport's national governing body.

Originally 25mm thick macadam – a substance similar to Tarmac – was to be laid over the existing track. But the final result would have been too lumpy to meet the federation's standards.

After lengthy discussions the council agreed the work should be upgraded.

Now an extra 60mm of macadam is to be laid, along with a new kerb.

Deputy Tory leader Alistair Thompson said: 'The Mountbatten Centre is an amazing project and will be fantastic when it's finished. It's just a shame the council had to find extra money to pay for this mistake.'

As reported in The News, the Mountbatten Centre has been chosen as a potential Olympic training site for the 2012 London Games.

Senior council figures say it wasn't an error but a choice to upgrade.

Councillor Terry Hall, in charge of culture and leisure issues, said: 'The Mountbatten Centre project has been going on for a long time.

'When it was originally planned we didn't have some things up to the same standard as we have now.

'The new surface is the British Cycling Federation's gold standard.

'It means we won't have to replace the track in a few years and I think it will really enhance it and bring it up to a standard for people to enjoy.'

Most of the cash for the improvements is coming from a pot of money set aside for improving parks and open spaces, while £14,599 is money saved from the building contract.

The new surface is due to be laid next week unless councillors object.

Work on the cycle track will be completed the week after but can't be used until work on the athletics track and grandstand is finished in November.