Royal Mail bosses have advised customers to travel outside Oxfordshire's borders before posting their letters, while staff continue their strike action.

Talks with union bosses were still deadlocked last night, as managers started taping up postboxes until the dispute is over.

More than 300 staff from offices in Oxford, Bicester and Witney were taking part in the unofficial strike, prompted by the suspension, on full pay, of a postman in Bicester.

Postal workers in Witney also staged a lightning strike on Monday, following the suspension of another postman.

Last night, businesses and residents were being advised not to post mail inside county borders. Spokesman Mike Dalton said: "I know it's not possible for everyone, but we would advise people to post mail outside Oxfordshire."

The union is planning a mass meeting at Oxford Town Hall in St Aldate's at 11am tomorrow to update members on the talks and hold a possible vote on a return to work.

Postboxes were being sealed in the OX1-5 and OX8 postcode areas, including central Oxford, east Oxford, Kidlington, Headington and Witney.

And as a contingency measure, mail waiting to be sorted has been taken out of the area to be dealt with by staff not affected by the dispute.

After postboxes were sealed, the area manager for Royal Mail Oxford, Kevin Oakley, said that the national leadership of the Communication Workers Union had issued letters urging their members on strike in the county to end the unofficial action. The mail strike has also prevented the delivery of Oxford City Council rent allowance payments. For further information, telephone 01865 252849.