...are going to be investigated. Accroding to the Financial Times: http://blogs.ft.com/westminster/2011/12/hmrcs-sweetheart-tax-deals-under-the-microscope/
Here's an interesting extract:
The names of all six companies being investigated are not yet in the public domain. I’ve just been reading evidence presented to the PAC this month which suggests that 435 companies have struck deals of over £10m in the last three years. (They are 36 deals of over £100m; 54 deals of £50-100m; and 345 deals of £10m-£50m.)
It seems big companies don't have to pay their tax bills in quite the same way as the rest of us.