Warburtons traditional heartland is the north of England but it has now overtaken Hovis as the biggest bakery brand in London.
The family-owned baker was founded in 1876 in Bolton, where the company is still based. It only entered the London market in 2003, when it opened a bakery in Enfield.
Now the brand has reached the top spot in the capital, with a 14.8% share of the bakery market.
It has overtaken Premier Foods owned Hovis and Allied Bakeries Kingsmill which have a 14.5% and 13.4% share of the London market respectively.
Warburtons said the recent growrh was driven not just by its sliced bread products, but also the popularity of its crumpets, sandwich thins, pittas and wraps.
Since opening the brand has gone from strength to strength in the south and have recently celebrated its 10th anniversary.