Mason, who joined the retailer in March, will cut ambient lines from 14,000 to 7,000 to simplify Somerfield's offer. The change follows a mammoth customer research project in which shoppers told the retailer that its ranges were too wide, its availability was poor and prices were uncompetitive.
Mason said that he has addressed these issues and is now trying to regenerate and grow the business, with EBITDA forecast to jump more than 50 per cent compared with the last financial year.
Somerfield has introduced the 7,000-line range into 15 stores with improved, lower shelving and a different category management approach, and has been encouraged by the resulting uplift in sales. It will now roll out the range changes across its 1,000 store portfolio by Christmas.
As a result of the range changes, Somerfield has increased availability in its test outlets.
The grocer has also reduced the number of in-store promotions and focused on lowering prices. Mason said that, before he joined, Somerfield had about 50 per cent more promotions than a Tesco supermarket in outlets that were a third of the size. Half of those promotions were taking less than£20,000.
Mason said: 'There has been a lot of change in the past six months. We have had to reboot the whole machine. We had inherited a very complicated Somerfield business. In the schools I've been brought up in - at Mars and Asda - the business starts and finishes with the customer and that is who we are going to focus on.'
Somerfield undertook 40,000 customer interviews in the first two months of Mason's tenure to help shape the direction of the business. Management is also spending two days a week in stores to get closer to the coalface.
Mason said: 'We are trying to create a better, simpler, faster Somerfield. We are trying to combine the operational effectiveness of a Tesco with the community credentials of what the Co-op used to be about.'
Somerfield will generate sales of more than£4 billion this financial year. It has a 4.6 per cent market share, according to TNS, for the four weeks to September 10.