Westminster City Council says many do not realise they must apply for a new licence whether or not they are interested in longer opening hours.

The new rules were designed to usher in a continental-style drinking culture.

But only a small number of pubs and restaurants have so far applied to extend opening hours, the council says.

Westminster City Council took over responsibility for licences from magistrates on 7 February.

It says that, so far, only 73 out of 3,600 premises have applied for new licences.

They have until 6 August to apply for a conversion to the new licence.

They could be breaking the law from 7 November if they are operating and have not had their licences converted to a new system.

A spokesman for Westminster City Council said: "Many businesses do not believe that they have to make this conversion to continue trading exactly as they do now. There has been no government advertising to explain that they require this."

Under the new regulations, venues have "grandfather rights" to apply for like-for-like licenses, covering the same criteria as their current licence, until 6 August.

The council spokesman added the new regime was "a leap in the dark" because there was no national guidelines for dealing with venues still trading without the new licences.

He said: "We wouldn't be closing venues down. That would harm the economic vitality of the West End and London."

The problem is not just confined to London - figures from Westminster City Council showed that of 1,500 premises in Newcastle, for instance, only 33 had applied for licences.

The government says it has sent letters to licensees alerting them to the changes.

The new system will cut bureaucracy and free up millions of pounds for policing, it says.