Oil workers have been flown off a North Sea platform because of a blocked drain.

About 20 workers were removed the Montrose Alpha, about 125 miles east of Aberdeen.

The blockage forced operator Repsol Sinopec to reduce the number of toilets available to crew.

Hot water was also in short supply and one worker reported a smell of excrement on the platform.

A spokeswoman said: "We can confirm a partial down-manning of the Montrose Alpha platform today.

"This is due to a blocked drain in the accommodation facility which has resulted in a reduction in welfare facilities available to crew.

"To ensure crew welfare is maintained, the decision has been made to instigate a partial down-manning of non-essential personnel until the issue is resolved."

About 110 workers will remain aboard Montrose Alpha, it is understood.