Every cloud of volcanic ash has a silver lining for the volunteers looking after Oxfordshire’s ancient watercress beds. Members of the Chiltern Society were meeting in their Watercress Centre at Ewelme when a RAF officer called in.

He was from the neighbouring RAF Benson airfield and asked if there were any jobs the aircrew could do.

As Tom Stevenson put it: “The aircrew were grounded because of the ash clouds from the Icelandic volcano and he wanted to find the men something to do.

“I asked how many people he was thinking of and he replied ‘about 40’. I said we could take a maximum of 15 at any one time.”

So the upshot was that two groups of aircrew turned up on two mornings and they were set the task of pulling up bullrushes and reed mace that were threatening to take over a section of the 6.5-acre local nature reserve at the site of the Ewelme watercress beds.

Tom added: “They had to use their hands to do the work, for which we were very grateful.

“As far as we are concerned we could do with more volcanic ash clouds if it means we have some volunteers to do some work.”

The unexpected arrival of extra muscle power was in line with the maintenance regime at the location.

“We have work parties drawn from members twice a month on a Wednesday and a Saturday and the number who come along varies. We also have help from the green gyms at Sonning Common and Wallingford,” said Tom.

More assistance comes from the village where the Friends of Ewelme Watercress Beds run quizzes and other events to raise money that is spent on tools and paying for things like electricity bills.

There is also some income derived from the £2 visitor charge.

It was just ten years ago this year that the Chiltern Society decided to buy the watercress beds at Ewelme to preserve a piece of local heritage and social history.

The 39 beds strung along about half a mile of the Ewelme stream had fallen into dereliction after commercial growing and selling had ceased in 1988.

Although the watercress beds are recorded as being in existence in the 1880s, they are believed to have been in the village for centuries.

Watercress is a member of the cabbage family and grows in the shallow, alkaline chalk streams of southern England. It contains vitamins A, C and D and is a source of iron, iodine and sulphur.

In Ewelme, the stream rises in the Chiltern hills near the village and flows beside the High Street and eventually into the River Thames.

After a corn mill on the stream burnt down, a George Smith of Lewknor bought the land adjacent to the stream and in about 1890 he began to dig out and widen the watercourse, creating the optimum conditions for growing watercress.

He built the structure of the 39 beds, including a central bund or wall to control the flow and depth of water.

Watercress was grown and sold until 1988 when it was thought that it fell out of favour as supermarkets stocked ever more exotic vegetables.

Until then, watercress from Ewelme was sold widely. It was cut and put into large wicker baskets and taken to Watlington railway station.

From there it was transported for sale in London, Birmingham, Manchester and Liverpool.

Ewelme watercress was also sold in several markets in Oxford, Abingdon and Wallingford.

When the commercial operation ceased, the beds became overgrown, although a father and son in the village did a lot of work trying to keep the beds clear of weeds.

However, they eventually had to give up the task.

The Chiltern Society then came to the rescue, recognising that the watercress beds were part of the local heritage.

Grants were obtained from the Heritage Lottery Fund, Nationwide Building Society and the Countryside Agency and a brick building replaced an earlier store.

In 2004 the new Ewelme Watercress Beds centre was opened by the Duke of Kent.

As well as maintaining the beds, members have been developing a nature reserve on their 6.5-acre site.

Tom, the nature reserve manager, added: “I think the reserve adds a lot of interest for members and we are also beginning to have educational activities where schoolchildren can come.

“They can take samples of the water and, using our microscopes, can find out what life it contains.”

The site has wet and dry meadows, a copse and a butterfly meadow.

So far, 80 different species of birds have been recorded, including little egrets and the elusive water rail that hides in the reedbeds while overwintering on the site.

A record is being compiled of butterflies and about 140 different moths have been logged.

Mammals visiting the reserve have included foxes, a badger and the endangered water vole.

The intrusive American mink has been kept at bay thanks largely to the fact that the stream goes into a culvert under a village road. It is thought this has deterred the mink, which is an enemy of the water voles.

While watercress can be a favourite ingredient of soup and sandwiches, members cannot sell their watercress.

“If we wanted to sell the cress the water from the stream would have to be analysed once a month at £50 a time.

“Although the stream is generally clean it could be polluted by the rainwater run-off from the village roads.

“The cress itself would have to be checked regularly too,” said Tom.

So the cress that has to be cut ends up being composted.

The watercress beds are open to visitors on the first Sunday of the month from May to September from 2pm to 5pm at £2 a head, children go free.

Guided walks are held on the first Sunday of the month from October to April from 10.30am.

Park cars in the village car park near the church and school.

For more information and to book tours telephone 01491 835173 or go to www.ewelmewatercressbeds.org