The closures will affect its clothing and home stores, which have underperformed for several years.
M&S named 14 stores earmarked for closure on Tuesday, with 21 already having shut.
The Bridlington outlet in East Yorkshire and Keighley store in West Yorkshire were both earmarked for closure later this year.
Bayswater, Fleetwood Outlet and Newton Abbot Outlet will close by the end of July 2018. Clacton and Holloway Road will both close by early 2019. Darlington, East Kilbride, Falkirk, Kettering, Newmarket, New Mersey Speke, Northampton, Stockton and Walsall are proposed for closure and will now enter a period of consultation with all 626 affected employees.
Sacha Berendji, retail and property director at M&S, said: "We are making good progress with our plans to reshape our store estate to be more relevant to our customers and support our online growth plans.
"Closing stores isn't easy but it is vital for the future of M&S. Where we have closed stores, we are seeing an encouraging number of customers moving to nearby stores and enjoying shopping with us in a better environment, which is why we're continuing to transform our estate with pace."