The discount clothing chain will see its market share rise to 7% while M&S will see a drop to 7.6%.
New data from Global Data has shown that Primark’s market share has risen steadily since 2008 when it stood at 4.5%, M&S has seen the complete opposite however with its market share falling from almost 10% in 2008.
Analysts expect Primark to overtake in the near future with many suggesting that it could happen as early as next year. In the 24 weeks before 3 March, Primark saw revenue rise by 8% up to £3.5bn and profits up by 6% to £341m.
The M&S figures make for stark contrast however with an almost 3% drop in sales down to £3.8bn, as the company accelerates its plans to close over 100 stores by 2022.
Maureen Hinton, retail research director at Global Data, said: “Marks & Spencer has dominated the market for decades, but its lead as number one is perilously close to being lost to Primark.
“The closure of yet more stores will hasten the decline unless it can shift the lost sales to its online channel and transfer to its other stores. But it also has to start growing total non-food sales to stem the overall decline.”
While M&S closes stores, Primark is opening more, including a brand new West London store that will create 500 jobs.