There are 7.5 million dogs in Britain, producing 1,000 tons of faeces a day.

There is no national legislation - only by-laws - to compel owners to clean up after their dogs.

The maximum fine is pounds 500. The maximum for litter is pounds 2,500 ( pounds 1,000 in Northern Ireland).

Toxocara canis is the roundworm carried by puppies, and some adult dogs. The eggs are expelled in the faeces. There is no obligation for owners to have dogs 'wormed'.

Toxocariasis disease can cause asthma, epilepsy and blindness, but also milder symptoms such as fevers and coughs. More than 200 cases are reported every year, mostly in children. Around eight children a month develop eye disease as a result of Toxocara infection.

Toxocariasis can be caught by swallowing soil contaminated by Toxocara eggs. The eggs can survive in soil for two or three years. They cannot be destroyed with disinfectant.

It takes two weeks for faeces to become infectious. Fresh faeces pose no threat from Toxocara. 'Poop-scooping' is therefore safe and effective.

Soil surveys of London parks have found two-thirds contaminated with Toxocara eggs.

The issue on which MPs receive most complaints is dog fouling.

'Poop scoops' are provided free by some local authorities; pet shops sell them for around pounds 3 for 20. Old plastic bags and bits of cardboard will do equally well.