Nearly £500million was wiped off the value of Melrose following a double downgrade.

Melrose shares fell 7.1 per cent, or 36.3p, to 474.7p, reducing its value by £471million.

While most analysts reckon the stock is worth buying, UBS broke ranks by advising clients to sell shares in the owner of the GKN aerospace business.

The bank said one of the FTSE 100 group's biggest sources of revenue is overvalued.

It believes the revenue and risk sharing partnership portfolio, which provides parts such as fan blades for engines and then takes a slice of profits once they are sold, is worth £2.8billion.

But that is less than half of the £5.7billion valuation cited by Melrose. 

As a result, UBS lowered its rating from 'buy' to 'sell' and slashed the target price from 770p to 400p. Melrose bought GKN, which made cannonballs used at the Battle of Waterloo and Spitfires for the Battle of Britain, for £8billion in a controversial deal in 2018.

It kept the aerospace division but last year spun off the GKN automotive, hydrogen and powder metallurgy businesses into a stand-alone company called Dowlais.

London's main markets ended the week in positive territory as the FTSE 100 rose 0.5 per cent, or 39.78 points, to 8327.78 and the FTSE 250 was up 0.4 per cent, or 84.78 points, to 21,189.48.

Across the Atlantic, Wall Street rallied after US Fed chairman Jerome Powell said the 'time has come' to cut interest rates.

BP has invested in a division of a Chinese company that makes sustainable aviation fuel.

The oil major bought a 15 per cent stake in a business owned by Zhejiang Jiaao Enprotech for around £37m, and edged up 0.7 per cent, or 3.1p, to 429.3p.

Evoke, which owns gambling outlets 888 and William Hill, snapped up the operator of the Winner business in Romania.

The firm will merge its division there with New Gambling Solutions in a group which will be led by Winner's chief executive Nicklas Zajdel.

Romania will be its fifth core market, joining the UK, Italy, Spain and Denmark. Shares added 0.2 per cent, or 0.15p, to 69.2p.

Hays gave up its gains of Thursday, falling 2.2 per cent, or 2.15p, to 95.25p, after the recruiter outlined further cost-cutting measures to combat continuing pressures in the hiring market.

Molten Ventures climbed 3.7 per cent, or 15p, to 422p just days after it said the value of its stake in Revolut has more than doubled to £160m now that the banking app was worth £35billion.

ADF, which rents out costume and make-up trailers to the UK film and TV industry, raised £10m through placing 20m shares at 50p each.

The company – up 4.9 per cent, or 2.5p, to 53.5p – warned it remained affected by the impact of the Hollywood strikes earlier this year.

Accesso Technology launched a £4m share buyback just a week after the ticket software provider warned subdued trading over summer and project delays in the Middle East will hit revenues. Shares rose 3 per cent, or 16p, to 560p.