Animal rights activists have halted live sheep shipments to Holland from a Northumberland port after its harbourmaster was allegedly threatened.

Police are investigating claims that Tweed dock boss Brian Watson received anonymous phone threats from an activist protesting about the renewed export trade from Berwick.

The protest began last week when animal lobbyists discovered that 1,700 sheep from the Scottish Borders were to be shipped to Holland, the first time in about 60 years the port had been used for live trade. This week they increased pressure on the port not to allow a second shipment.

Mr Watson said: "We had a great number of calls from animal rights groups against this trade and the exporters have decided to call it a day after just the one trip.

"The vast majority of callers were perfectly rational and civil, just groups making their views known, but they weren't threatening. However, there were some that were quite threatening. Now we would just like the matter to rest."

A police spokesman said: "Following last week's shipment of sheep there was one incident of a phone call from an unidentified man who made unspecified threats regarding live-animal exports which were directed at the harbour. We are monitoring the situation."

Advocates for Animals campaign director Russ Minett said activists from a number of organisations had contacted the harbour to protest.

"Certainly there was no personal intimidation from Advocates for Animals," he said. "The export company have announced they are not going to send any more shipments through Berwick and obviously we are delighted."

Fellow activist Les Ward said: "For years we have campaigned for an end to this trade and it had virtually disappeared. The problem is not on this side. We would expect that to be in order. The concerns have always been with the other side and what happens to animals there."

Northumberland NFU chairman Stoker Frater, of Alnwick, said continental buyers would not accept slaughtered animals.

"It is vital that we are able to export livestock, but no-one likes to send live sheep away on the boat."

Country Land and Business Association North-East chairman John Cresswell said: "At a time when UK agriculture needs to expand its markets, the export of live lambs from Berwick to Holland appeared to be a move in the right direction.

"The welfare of animals is central to the way farmers in the North-East operate. But we must be allowed to get the food to the people. Irrational bully-boy tactics would not be permitted in any other industry, yet appear to have succeeded in stopping legitimate businesses from trading."