The Queen's English was rated as the easiest to understand
More than one-third of employees have changed their accent in order to impress their boss and improve their career prospects, research suggests.
Among the 1,000 people surveyed, 38% of those with a regional accent said they had had difficulties being understood, the Bury Technologies survey found.
The Queen's English came out top in terms of being the easiest to understand and the most professional.
The Liverpudlian, Mancunian and Midlands accents came out bottom.
Home counties' accents came second in the overall regional rankings, followed by Irish and Scottish.
The London accent came in 10th out of the 13 regions included.
"Everyone has an accent and, within the UK, accents change noticeably about every 25 miles," said David Crystal, professor of linguistics at the University of Bangor.
"The survey shows that people have now learnt to use different accents and alter their speech, depending on the situations in which they find themselves, to their best advantage."
Of those surveyed, Liverpudlians were the most willing to change their accent, closely followed by people from the Midlands.
However, not one Irish person admitted to having changed their voice for either professional or personal reasons.
Bury Technologies, an in-car equipment firm, commissioned the research from ICM.