The London market opened on the back foot weighed by miners and a drop in the oil price.
The FTSE 100 Index fell 43.8 points to 6266.2, as Brent crude slipped 0.9% to just under 45 US dollars a barrel.
Miners were also lower, with Anglo American 31p down to 701.5p, BHP Billiton falling 40.7p to 946.9p and Rio Tinto slipping 72p to 2262.5p.
The fall in the London market follows a slump of 71 points on Friday, again prompted by declining commodity prices.
Beleaguered high street department chain BHS is expected to file for administration today, threatening almost 11,000 jobs.
The privately-owned retailer has reportedly sent a letter to staff, which said it will call in administrators after being unable to secure a rescue package to save the 88-year-old business. A formal announcement is expected at around noon.
Joe Rundle, head of trading at ETX Capital, said: "The same pressures that squeezed the life out of BHS are being felt across the UK retail sector today."
However, the effect on other retailers was mixed.
Sainsbury's and Tesco were both down - 3.7p to 288.p and 2.2p to 184.5p respectively.
But Marks & Spencer edged up 0.9p to 428.9p, while Dixons Carphone lifted 1.8p to 422.3p.