Rail bosses have said a fresh rail strike announced by the Rail Maritime and Transport union (RMT) will have an "intolerable" affect on passengers.

Arriva Trains Northern has said it is "surprised and frustrated" that the RMT has rejected an improved 4% pay offer and called fresh walkouts.

The union has announced that station and ticket staff will strike for 48 hours from 2100 BST on 29 May, while conductors will stage two 24-hour strikes, on 1 and 7 June.

But Stan Herschel, RMT regional organiser, told BBC News Online: "I can only gauge passenger's feelings when travelling or at the picket line.

"And I believe they know we are working for a terrible company."

The offer was made following strong indications from the union that it would be acceptable

Ray Price, Arriva managing director

The RMT is angry that Arriva has given drivers an 18% wage increase, while offering other staff a much lower rate.

Mr Herschel said: "They say they are surprised at the union's decision, which I think insults the intelligence of our members.

"This is a company that has made millions in profits, increased shareholders' dividends, and pays its chief executive more than �500,000, yet they express surprise at our decision."

Ray Price, Arriva's managing director, said: "After considerable discussions, we are surprised and frustrated that the RMT executive has rejected this offer.

'Unrealistic demands'

"The offer was made following strong indications from the union that it would be acceptable.

"We have made a genuine and fair offer in a bid to resolve the dispute.

"We are also extremely disappointed that the union has not taken the opportunity to put the offer to a vote by its members.

"The strike action is having an intolerable effect on our customers and we share with them, and many others across the north of England, a frustration that these disputes are continuing in the pursuit of the union's unrealistic pay demands."