Sainsbury’s, The Co-operative, Waitrose and M&S all removed caged eggs from their shelves some time ago but in the last three weeks, following Tesco and Aldi’s announcements, Morrisons, Iceland, Lidl and Asda, plus international food service company, Sodexo have all committed to go cage-free.

These pledges follow a domino effect of similar announcements by leading supermarkets and other food companies in the US.

Asda had previously been criticised as the last of the major supermarkets to make a cage-free commitment, despite parent company Walmart's pledge to go cage-free in the US.

An Asda spokesperson said: "In line with our parent Walmart, our ambition is to phase out eggs from caged hens by 2025 in a way that supports a sustainable supply chain and that also enables us to continue to offer our customers the choice and value that they expect from Asda."

The transition to cage-free was galvanised by a petition from teenager Lucy Gavaghan, which gathered over 180,000 signatures. On the petition website, Ms Gavaghan thanked supporters of the campaign and vowed to take the issue to the next level.

"At current, the pledges made by Asda and Morrison’s only extend to whole shell eggs," she said.

"This means that the eggs hidden in own brand products such as cakes and bakery items are not necessarily required to contain non-cage sourced eggs. To me this is not a balanced commitment.

"If these supermarkets really want to improve the way hens are treated, they must make a change that is not exclusive to whole shell eggs."

Animal welfare organisation Compassion in World Farming said the commitments represented a fundamental step change in modern egg production, with an extra 4 million hens per year out of cages by 2025.

Dr Tracey Jones, Director of Food Business at Compassion in World Farming, said: “The speed with which these announcements are being made demonstrates the power of market shift when forward thinking brands lead the way and act as a catalyst for change. It is a time of major change for laying hen welfare in the UK and the hope that a cage-free day will dawn in modern egg production looks increasingly feasible.”