Brighton's sewers are the only ones in the country open to the public and are held up as an example of Victorian civil engineering.

But the idea of a trip down them immediately conjures up images of murky tunnels dripping unspeakable browny-green gunge on to the heads of rats.

The reality was not so sordid, although the only thing between visitors and Brighton's 22 million daily gallons of sewage was a hard hat and a pair of disposable gloves.

You feel sewers should have been sanitised to protect innocent eyes from the horrors of human waste.

But the stuff running through hundreds of miles of tunnels and pipes is on its way to be treated at Portobello and in its natural form.

All the usual waste that goes down the plughole goes floating past - and a lot more besides.

Southern Water employee Stuart Slark said: "I've seen rings, necklaces, kettles, shopping trolleys and car tyres. We even found a finger once.

"We rescued an owl from underneath the Old Steine and foxes sometimes fall in through open manhole covers.

"We also have a big problem with kids. We found a group of six-year-olds down there smoking."

There is also the danger of leptospirosis, a type of jaundice carried in rats' urine. It is treatable but can be fatal.

Brighton's sewers make for a fascinating trip, especially when you realise much of the huge network is the original structure and still needs very little maintenance.

In 1865, work began to build 44 miles of salt-glazedware pipes and brick tunnels.

A cement-sand mix was used to lay the bricks and visitors can still see bits of shell from Brighton beach.

At £104,000, the whole operation went £40,000 over budget, mainly because contractors had trouble with the amount of water encountered.

Catchpits were built to collect road grit and stones. These must be cleared by hand by the ten men who work full time to maintain the system.

On a sunny, busy day stepping down into the sewers at the entrance next to the Palace Pier is a strange experience. The volume is turned right down and the air is cool.

Visitors are taken round in groups of up to 25. At one stage, you step over a grill with the waste gushing past a few feet below.

The sewers do smell but you quickly get used to it.

The tour ends at a ladder, which leads to a manhole cover opening out on to the Old Steine.

The sewers are open to the public from May 7 until September 3, at £7 for adults and £3.50 for children. Call 0845 2780845 to book a tour.