I know this is "old news." I only link to it because when I have previously mentioned here and elsewhere that I knew of demands for bribes from Health & Safety Executive employees, I was asked if I was sure it was true.
I believe what I was told but understandably my informant would not be interested in pursuing the matter. He is still in business and has to deal with these people every day.
As you see the Chartered Institute of Building is conducting research but currently estimates that corruption costs the UK industry £3 billion per year.
"corrupt practices can be found at each phase of a construction project; during planning and design, in the award of contracts, during the construction process, and during the operation and maintenance of projects"
Of course, it's not proof that the story I was told is true. That I frankly cannot provide. However, it does suggest that it's likely.