(Sharecast News) - London's FTSE 100 was down 0.4% at 10,623.19 in afternoon trade on Monday.

Centrica was a high riser as Citi reiterated its 'buy' rating on the shares and said any weakness was a buying opportunity following the share price fall on Friday after Chancellor Rachel Reeves said the government was considering cutting the link between electricity and gas prices.

"We do not agree with the magnitude of the move given the short dated generation assets (old nuclear) at Centrica, bulk of which is expected to be closed towards end of the decade (we assume in our forecast all but Sizewell B is close by 2030)," the bank said.

"Even if we were to aggressively mark down all merchant nuclear to zero (ignoring a part may move onto RAB model), the impact on our sum-of-the-parts valuation is circa 3.5%."

Citi said the market's focus on earnings per share impact alone is incorrect and that it also needs to reflect duration in its approach. "In a sector that's fully valued, we still see better risk/rewards at Centrica," the bank said.

"We reiterate our buy rating and see any weakness as an enhanced buying opportunity."

SSE was also in the black, recovering from Friday's losses.

Oil giants BP and Shell gushed higher in tandem with oil prices, while defensives Reckitt Benckiser and British American Tobacco also rose.

On the downside, Metlen Energy and Antofagasta were the worst performers on the index as copper prices fell.

Cyclical stocks such as banks and housebuilders slumped amid worries about escalating tensions between the US and Iran, with Persimmon, Barratt Redrow and NatWest all lower.

FTSE 100 - Risers

Centrica (CNA) 203.90p 3.34%

BP (BP.) 555.10p 2.92%

SSE (SSE) 2,530.50p 2.61%

Tesco (TSCO) 493.85p 2.28%

Reckitt Benckiser Group (RKT) 5,112.00p 2.16%

Shell (SHEL) 3,254.00p 2.00%

British American Tobacco (BATS) 4,201.00p 1.45%

Admiral Group (ADM) 3,411.00p 1.16%

Vodafone Group (VOD) 115.75p 1.09%

Sainsbury (J) (SBRY) 354.70p 1.08%

FTSE 100 - Fallers

Metlen Energy & Metals (MTLN) 33.98p -4.47%

Antofagasta (ANTO) 3,795.00p -3.99%

The Sage Group (SGE) 895.60p -2.82%

Persimmon (PSN) 1,170.00p -2.66%

Rolls-Royce Holdings (RR.) 1,275.40p -2.64%

Entain (ENT) 616.80p -2.50%

NATWEST GROUP (NWG) 610.40p -2.46%

Barratt Redrow (BTRW) 270.50p -2.24%

Weir Group (WEIR) 3,110.00p -2.20%

Melrose Industries (MRO) 554.40p -2.19%