Once its merger with Portman building society has been completed, Nationwide should be able to offer cheaper mortgages, improved savings products and lower charges, chief executive Philip Williamson said, according to the BBC.

The proposed merger, which is still pending approval from Portman members and regulatory authorities, will create the largest mutual society in the UK, which Mr Williamson said will be preserved as the combined company will not be demutualized.

Adding more details to the development, which will see the new entity become the second largest mortgage provider in the UK, Matthew Wyles, a Portman director, told the BBC that members of his building society will get a windfall of at least GBP200.