(Sharecast News) - London's FTSE 100 was down 0.1% at 10,508.79 in afternoon trade on Thursday.

Diploma surged to the top of the index as it upgraded its full-year guidance following a "very strong" third-quarter performance.

The company now expects FY26 organic revenue growth of 14%, up from 12% previously. It also expects operating profit growth of around 42%, representing a further 7% upgrade to consensus.

Weir, Spirax, IMI and Smiths all rallied as FTSE 250 engineer Rotork agreed to be bought by Swiss engineering company ABB in a £4.1bn deal. Rotork was up a whopping 67%. Under the terms of the acquisition, ABB will pay 506p per share in cash. This comprises 503p and a dividend of up to 3p. This represents a premium of 73% to the closing Rotork share price on Wednesday.

On the downside, St James's Place tumbled following a report that two more of its large appointed representatives have left the network.

According to Bloomberg, Sheffield-based Prospera Wealth Management and Southeast-based Wellesley Investment Management are no longer in the network.

Miners Antofagasta, Anglo American, Fresnillo and Rio Tinto all lost ground.

FTSE 100 - Risers

Diploma (DPLM) 7,090.00p 4.87%

Metlen Energy & Metals (MTLN) 43.10p 4.01%

Weir Group (WEIR) 2,480.00p 3.07%

Spirax Group (SPX) 6,840.00p 2.78%

Kingfisher (KGF) 290.80p 2.39%

IMI (IMI) 2,920.00p 1.60%

Vodafone Group (VOD) 113.85p 1.52%

Smiths Group (SMIN) 2,550.00p 1.43%

Diageo (DGE) 1,552.00p 1.31%

Bunzl (BNZL) 2,752.00p 1.25%

FTSE 100 - Fallers

St James's Place (STJ) 1,132.00p -6.06%

Antofagasta (ANTO) 3,591.00p -4.04%

Flutter Entertainment (DI) (FLTR) 8,130.00p -3.44%

Centrica (CNA) 171.30p -2.70%

SSE (SSE) 2,405.00p -2.43%

Anglo American (AAL) 3,472.00p -2.31%

Fresnillo (FRES) 2,461.00p -2.19%

Rio Tinto (RIO) 6,708.00p -2.09%

National Grid (NG.) 1,208.50p -2.06%

Rolls-Royce Holdings (RR.) 1,362.80p -2.04%