A bitter dispute has broken out between a farmer and the RSPB over flooding on an Oxfordshire farm.

Tenant farmer Terry Moore has accused the RSPB of flooding 20ha (50 acres) of land at Otmoor Farm after the charity left a drainage pump running into a river for four days last week at Otmoor nature reserve.

See also: VIDEO: Flood-hit livestock farmer speaks out

But the charity has strongly denied it has done anything wrong. Instead it has blamed a combination of torrential rain and arable farmers further upstream for “non-stop” drainage of their farmland.

Mr Moore, who manages Otmoor Farm, Horton-cum-Studley, hit the headlines last month after more than 90% of his farm was flooded out following record-breaking rainfall.

He said: “I went out to my fields last Thursday night (27 February) and saw the water pooling out, straight down on to them. The ditches were overflowing and all the fields were flooded again.

“We had a lot of rain and then we have to cope with all that extra water. In my opinion, if they [the RSPB] hadn’t pumped out all that water, the main ring ditch and the dykes would have coped.

“It’s a matter of using common sense, but the RSPB seem to be a law unto themselves.”

His farming neighbour’s fields of maize had also flooded, he added.

The RSPB notified the public last Tuesday (25 February) of its plans to pump water off Otmoor reserve and into the river to boost rare bird populations.

In an announcement headed “Rediscovering the grass”, the charity explained how the floods were “finally receding”, so it was time to “shift some of the water from the fields”.

Therefore, it had “dropped the sluices and turned on Greenaway’s pump to aid drainage”.

The RSPB explained the plan was to “rediscover the grass and allow it to grow” to put it in an “optimal condition for the breeding waders”.

The breeding season for nesting birds normally begins in March or early April and lasts until the end of July.

The RSPB said that during the breeding season, it would allow its fields to “draw down”, to reduce water levels continually, a few centimetres at a time until the fields were almost dry.

David Wilding, RSPB Otmoor site manager, confirmed the charity had pumped water off its fields over four days using a single drainage pump. But he did not know how much water had been drained off in this time.

However, he insisted the charity’s actions had nothing to do with Mr Moore’s fields flooding again. “We had the pump running for a few days because we were draining water out of one of our fields,” he said.

“The pump was on for four days. All the river levels were low during that point. The river was not flooded when we put the pumps on.

“Even if we had our pump running across the whole of the Otmoor basin, the water would make millimetres of difference [to river levels].”

Mr Wilding said the RSPB had sacrificed its fields just as much as everyone else in the area.

However, he shifted the blame to the torrential weather at the end of last week and cited arable farmers in the area who he claimed were pumping water off their land around the clock.

“The flooding has definitely not been caused by us. There are arable farmers who have been pumping water for the whole period,” he said.

“Legally, we could use pumps all the time if we wanted to, but we don’t. But because it’s the RSPB that owns the fields, now the finger points at us to say: ‘You cannot pump at all now’.”

In January, Farmers Weekly exclusively reported how Mr Moore’s farm had been devastated in the recent floods, with more than 90% of fields under water – up to 6ft high in places.