In June 1971, Sunair bought Lunn Poly from the THC for £175,000. The next year, the company became part of Thomson Travel Group, along the way it acquired ten John Camkin Travel shops in the Midlands – which increased the number of shops from less than 30 to nearly 500 by 1990. It is now owned by TUI UK & Ireland, part of the German conglomerate TUI Group AG.
When TUI UK rebranded Britannia Airways as Thomsonfly in November 2003, the company insisted that there were no plans to rebrand Lunn Poly. On 2 November 2004, however, the announcement was made that Lunn Poly was to be rebranded as Thomson in order to create a "powerbrand". TUI UK & Ireland announced that all 780 Lunn Poly shops in the United Kingdom would be renamed to Thomson before the peak holiday booking period started on 26 December 2004.
Lunn Poly was famous for a long running advertising campaign on television. These commercials featured people looking into what holidays the company offered. Another person would then say to them in disbelief "Lunn Poly? Get away!", at which point the person would disappear into thin air and end up at a vacation spot.