Supermarket giant Asda has been accused of using a proposed pay rise as a "smokescreen" for unpaid breaks and shortened night shifts.
The grocery firm recently announced a set of potential contract changes for its workforce, pledging to hike the basic hourly rate of pay for retail employees.
However, Labour MP Siobhain McDonagh wrote in a letter today that the new changes would include "a loss of paid breaks, an end to premium pay, and a shortening of the night shift" that would make 2,700 staff members up to £500 worse off every year.
The Mitcham and Morden MP added that a further 300 employees were set to lose "more than this amount".
She claimed that the potential changes would also result in night shifts being reduced to five hours, between 12am and 5am.
"I welcome any increase in basic hourly pay – but this must not be used to disguise a significant pay cut for 3,000 of your most longstanding staff," McDonagh concluded in her letter to Asda chief executive Roger Burnley.
In a letter of response to McDonagh this afternoon, Burnley wrote: "As a retailer, our job is to serve our customers’ needs. That means we need to have the right colleagues in the right place at the right time. As our customers change the way that they shop, we need to ensure that we have the flexibility to change with them in order to remain competitive."
He wrote that it would "not be appropriate to comment on the potential impact of our proposals on individual colleagues at this early stage, when we are currently engaged in ongoing dialogue with the appropriate representative bodies about the nature and scope of any potential changes."
McDonagh replied that "the position is still that 3,000 hard working Asda staff are set to earn less as a result of these proposals".
"However you slice and dice it, that is the case. Many of these loyal staff work tirelessly through the night in order to earn more to meet their family’s needs, whilst Asda proposes this shocking pay cut in return."
An Asda spokesperson added that the proposals would enable the group "to deliver better service to our customers in an intensely competitive marketplace and would make 95 per cent of our colleagues financially better off."