Former Tesco chairman and chief executive Lord MacLaurin has urged Tesco’s board to back chief executive Philip Clarke after saying he was “saddened” by Sir Terry Leahy’s legacy.

MacLaurin, who led the business through rapid out-of-town store expansion before appointing Leahy in 1997, said Clarke needs time to fix the UK business.

Speaking from the audience at Tesco’s annual general meeting in London today, MacLaurin said: “When you judge his legacy, it’s very sad. This company is not going to be fixed overnight. It is a two- or three-year job and I urge you [current chairman Sir Richard Broadbent] to give Philip Clarke and his team time to do this.”

Clarke is in the process of turning round the grocery giant after calling time on Leahy’s US venture Fresh & Easy and reporting a 50% fall in annual profits in April. Its core UK business has faltered since Leahy left in 2011 as non-food sales in large stores have struggled.

Broadbent said that Tesco’s directors are in the process of learning from mistakes in the US and said the grocer has learnt “it’s a good idea to pilot your ideas before you roll them out on a large scale”.

Broadbent said Tesco has switched away from “giving primacy to quarterly like-for-like sales” opting to create long-term, sustainable profits.

Clarke said: “It’s a new era of capital discipline for Tesco. Introducing sustainable and consistent returns year in, year out.”

Broadbent added that nothing is fundamentally broken at Tesco, which issued its first profit warning in 20 years last year. “It is there to be reinvigorated. This is not a reinvention, it’s a rediscover.”

Clarke said that, despite writing down £804m in property assets earlier this year, that Tesco would continue to open stores of convenience size or food-focused supermarkets. He said he did not anticipate opening any stores more than 65,000 sq ft as non-food sales have migrated online.

In an at times fiery AGM, Tesco’s approach to stocking lads mags, re-invigorating the high street and CSR were all questioned. Clarke said that its Tesco Express format has helped drive footfall to the high street in answer to calls for it invest in cheesemongers and fishmongers and bring its F&F clothing offer to the high street.

All of Tesco’s proposals were approved by shareholders at the meeting.