Mark Hemingway will take a career break in June before rejoining the industry 'as a freelance PR consultant or to work with one of the leading financial PR agencies in London'.
Hemingway joined Halifax in 1982 as a management trainee, before becoming one of the founder members of the Halifax press office in 1988. Before then the company did not have a working press office function.
He has seen the bank through major changes, including a £10.8bn merger with the Bank of Scotland in 2001.
'I've had 25 marvellous years at the Halifax and will be very sad to leave,' said Hemingway. 'The press team at Halifax are fantastic and they will undoubtedly continue to lead the field in PR. However, now is the right time for me to take up a new challenge.'
The Halifax press team has been successful during Hemingway's tenure, picking up PRWeek Private Sector Department of the Year 2006, European Campaign of the year 2006 at the Sabre Awards as well as topping the Mori Business, City and Personal Finance polls for the past six years.
But, as Britain's largest mortgage lender, the bank has felt the effects of the credit crunch as much as any. It reported house prices falling by 2.5 per cent in March - indicative of the market downturn in which it is operating.
In a difficult market, reports earlier this month suggested Halifax is to raise interest rates for mortgage borrowers taking out larger home loans and stop doing business altogether with customers who cannot find deposits of at least five per cent.
In late March around 250 directors and senior staff of Halifax Bank of Scotland (the post-merger group name) snapped up more than £6m worth of the bank's shares. They did so a day after the mortgage lender slumped 17 per cent (it later rallied) following rumours it was facing Northern Rock-style liquidity issues.
Chief executive Andy Hornby said the move was a 'demonstration of confidence' in the stock. Hornby splashed out more than £400,000 on 92,812 shares with his annual cash bonus last Thursday.