Blue chip shares were decidedly flat on Friday (3 March) as the FTSE 100 retreated from record highs seen earlier in the week to 7364.14, down 0.25% or 18.21 points at 1:32pm GMT, after UK Culture Secretary Karen Bradley expressed "concerns" about the proposed merger between Sky and 21st Century Fox.

In a statement, Bradley said she was "minded" to push for the deal to be investigated but stressed that she has not yet taken a final decision on whether or not to intervene. In response, Sky's shares fell before staging a minor recovery to 995.50p, still down 0.30% or 3p.

However, the broadcaster was not the biggest blue chip faller of the afternoon. That dubious accolade went to WPP (-8.53%), which warned that global conditions in the advertising market are likely to be more challenging in 2017 as a result of "tepid economic growth".

The share price decline came despite the fact that WPP's profit before interest and tax rose by 22% to £2.16bn ($2.65bn) in the 12 months to 31 December.

Nicholas Hyett, equity analyst at Hargreaves Lansdown, said: "While few were complaining about WPP's financials, it wasn't the headline numbers that were the problem. The group confirmed 2017 has got off to a weak start, and went on to provide a more downbeat outlook than analysts expected."

Among the other major FTSE 100 fallers were Fresnillo (-3.57%), Hikma Pharmaceuticals (-2.84%), London Stock Exchange Group (-2.41%) and Paddy Power Betfair (-2.03%).

While gains on the blue chip index were muted, Old Mutual (+1.67%), Standard Life (+1.64%), BHP Billiton (+1.30%), 3i Group (+1.08%) and Associated British Foods (+1.02%) were among the better performers.

The FTSE 250 also headed lower, trading at 18,841.10, down 0.58% or 109.75 points, with textile maintenance services provider Berendsen (-13.72%) being among the session's biggest fallers, after it revealed expectations of a difficult year ahead.

Hochschild Mining (-5.92%), Cobham (-4.04%), Cairn Energy (-3.51%) and Travis Perkins (-3.27%) were other major fallers. Going the other way, Shawbrook Group (+4.71%) and Hunting (+3.61%) notched up decent gains among the midcaps.