Paywall, but The Times helped the investigation, so not unreasonable.
Gist is: Sugar tried to claim he was non-dom, to save £186m in tax. However, members of HoL are officially classed as residents (because Jesus, imagine someone deciding on the laws of the country while not even officially living there)
Additionally, he's quoted in the article saying that if he was aware, he would have stepped down...So his HoL membership is now being reviewed on the grounds that he was ready to drop his duties the moment it was convenient to him.
He's a chavvy spiv.