How do you determine if costs are "falsely" attributed?
Let's take Apple and Google as examples. Apple mostly sells things, which they have manufactured for a given price, wholesale at a higher price, and retail at an even higher price. For the sake of argument let's say all their sales are iPhones, which all cost $200 to manufacture, wholesales for $600 and retails for $650 (I'm ignoring ALL fixed costs here to keep this simple)
Google sells mostly ads, which cost them essentially zero to deliver but they obviously have some considerable fixed cost in running their servers, their engineers, etc. and a by comparison small cost in staff to sell the ads.
So what's the profit when Apple sells an iPhone in the UK? I'm guessing you're going to argue that it is $450, but FASB says it is $50 and a country that ignores FASB in their laws for something this basic will find business fleeing fast enough that the extra revenue the law brings in won't compensate for it.
What's the profit when Google sells 1000 ad packages for $1000/ea, and have two UK ad sales people making $100K/yr (convert this all to pounds in your head if you're in the UK) Is that an $800K profit? Of course not, they have some fixed costs, but allocating those is a lot more tricky. Is the UK government going to be in charge of how Google does its books, to insure they aren't lading more cost into the UK than what the UK thinks is "fair"?
Almost all the engineers designing the clever algorithms that make those targeted ad packages worth $1000 instead of $10 work in the US, so should their contribution to the value of those ads in the UK be ignored because Google isn't creating jobs in the UK doing that work? Maybe the UK government can find a way to get them to pay more, but there will probably be another loophole found pretty quickly by one of the companies with a similar 'services' based business that the others will quickly copy.
If the UK wants to fix this, they need to undo some of the tax treaties they have with other countries that these companies are exploiting. They can't attack it as a problem of where companies attribute cost, unless they want to make the UK a pariah amongst multinationals.