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More on that decision by a group of 50 states and territories in the US to launch an investigation into Google's dominance of the online advertising market.

The action adds to a mounting number of probes of big technology firms by US authorities.

Rathbones investment director Jane Sydenham told the Today programme: "This is much more akin to the way European regulators have been thinking.

"Europe has been ahead of the US in its approach to how the tech companies behave and has already fined Google some $9bn, so the US is really catching up as far as Europe is concerned.

"Tech is some 25% of the US stock market in terms of value, whereas in Europe it's a much lower percentage, so the price the US can pay in terms of the economy and stock market could be high if this becomes an ongoing problem."

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A group of 50 states and territories in the US have launched an investigation into Google's dominance of the online advertising market.

Dawn Chmielewski, senior editor technology, media and entertainment at Forbes, told Radio Five Live's Wake Up To Money it is not that shocking that California, the state where Google is based, is not part of the action.

Google itself is "simply huge".

"The question the attorney generals will ask whether it is crushing competition and limiting consumer choice," she said.