A litter 'league table' is on the way to reveal which parts of London are kept cleanest - and shame London's dirtiest boroughs into taking drastic action.

The initiative to tackle the capital's growing problem was launched yesterday at a conference attended by John Gummer, the Secretary of State for the Environment.

The Tidy Britain Group (TBG) announced its scheme as figures from the royal parks department showed 15 tons of rubbish was picked up on Sunday in the eight parks it administers in the London area. It was mostly made up of the leftovers from picnics.

At yesterday's launch, local authorities heard how urgent action was needed to prevent London being swamped with rubbish.

Research by the TBG suggests chewing gum and cigarettes are the biggest nuisance and represent almost 40 per cent of rubbish dropped.

Londoners will soon be able to read in a directory just how clean or dirty their borough is compared with others.

Trained litter snoops, working in teams of four, will survey all 33 boroughs in secret during September, taking photographs, noting the incidence of dog fouling, discarded cigarettes, fast-food wrappers and other evils.

The directory will be published in February by the TBG - funded by pounds 2.9m this year by the Government - is intended to shame the worst boroughs into action.

Surveyors will grade streets according to the amount of litter.

A:. Litter is absent;

B: It is there, but bitty;

C: The street is in a crummy state;

D:It is downright disgusting.

TBG recently placed London top of nine capitals in its European City survey.

But it was criticised for having glossed over the problem because it concentrated only on Westminster and central tourist sites such as Trafalgar Square and the Houses of Parliament.

At yesterday's launch, John Gummer said of the 12-month assessment - part of the Cleaner London Programme - that ministers were now tackling litter in London as a whole.

Sandra Palmer, for TBG, said the 1990 Environmental Protection Act had made councils adhere to a defined standard for the first time.

'All councils have to conform to Grade A now. If this is found not to be the case, the council has a set time period in which it must put things right.

Special projects in 40 areas deemed to have potential waste management problems are planned. These involve housing estates in Greenwich, main shopping streets in Haringey, schools in Southwark and the South Bank area.

In Lambeth residents are so fed up that they go out collecting rubbish themselves.

Streatham Litter Action Group said: 'There are now about fifty volunteers on call and we can collect hundreds of bags of litter after a couple of hours.

'The council is working with a consultant from the Tidy Britain Group, but says it cannot afford to improve its service.

Tourist authorities are also concerned that other sites may have been left vulnerable because of the previous focus on keeping the West End clean.

Hampton Court, the Tower of London and many other museums all fall outside the central area, they note.

(Photograph omitted)