My understanding is that Sugar was absent from the UK for a large part of the tax year in question because he was working on the Australian version of The Apprentice. As such he may have become liable for tax in that country.
Anybody has the right to question whether a prolonged absence from the UK affects their liability to UK tax. Any UK national working overseas has the right to do that. Multi-national companies who second UK nationals to overseas projects, structure employee absences and returns to the UK to minimise tax exposure.
I don’t know who was responsible for the oversight regarding the provisions of the Constitutional Reform and Governance Act 2010 (the CRAG act). This overrides all of the automatic residency and ties test which normally determine liability to UK tax. Arguably Sugar should have known, especially as his life peerage was awarded not long before the legislation was introduced and would surely have been a hot topic among his fellow peers. OTOH, he pays other people to know these things. A tax accountant dealing with high net worth individuals (HNWI) should have known, unless their client porfolio had never included members of either Houses. Sounds like a rookie error to me. Maybe someone will end up being fired as a result.
Of general interest:
The provisions of CRAG received Royal Assent on 8 April 2010. There were transitional provisions which allowed life peers to withdraw from the House if they did not want the legislation to apply to them. Five did withdraw in order to retain their advantageous tax status. These were:
Lord Laidlaw (Scottish born business man, racing driver - became a tax exile in Monaco)
en.wikipedia.org/wiki/Irvine_Laidlaw,_Baron_Laidlaw
Lord McAlpine of West Green (construction empire, advisor to Thatcher, another Monaco tax exile)
en.wikipedia.org/wiki/Alistair_McAlpine,_Baron_McAlpine_of_West_Green
Baroness Dunn (Hong Kong born financier (HSBC) who unsuccessfully lobbied to allow the people of Hong to have the right of abode in UK after control ceded to China in 1997.
en.wikipedia.org/wiki/Lydia_Dunn,_Baroness_Dunn#External_links
Lord Bagri (Indian born, chair of London Metal Exchange and advisor to Prince’s Trust. In 2012, Bagri sold Hanover Lodge, "the UK’s most expensive home", to Russian billionaire Andrey Goncharenko (Gazprom), for £120 million.
en.wikipedia.org/wiki/Raj_Bagri,_Baron_Bagri
Lord Foster of Thames Bank (Norman Foster architect English born tax exile in Switzerland)
en.wikipedia.org/wiki/Norman_Foster,_Baron_Foster_of_Thames_Bank
www.standard.co.uk/hp/front/architect-norman-foster-gives-up-seat-in-lords-over-taxes-6489403.html