Deliveries could slip if Post Office staff vote for strikes

The Royal Mail said 93% were delivered on time in June - the best performance for five years.

Postal chief praised employees for improving delivery times with such hard work, but chief executive Adam Crozier warned the current strike threat was undermining customer confidence.

Consumer watchdog Postwatch also welcomed the improved performance, but added that a million letters are still failing to reach their destination the next day.

It added the postcode area that saw the best performance for first-class post was Sheffield - with 92.5% of deliveries arriving on time in the three months to June.

'Struggle'

The worst performing area was south west London with only 87.5% of first-class deliveries arriving on time.

Postwatch chairman Peter Carr said: "Royal Mail is struggling to reach the majority of its targets this year even without a strike."

The latest figures come as 160,000 Communication Workers Union (CWU) members are voting on whether to strike over a dispute on pay.

The CWU has rejected an offer of a 4.5% pay increase over 18 months because of the many conditions attached.

Talks between the union and the Royal Mail at the conciliation service Acas were suspended on Wednesday with both sides far from reaching a compromise.