BIL, which is controlled by Malaysian tycoon Quek Leng Chan, drafted in a team of Brunswick M&A experts - via its UK bank HSBC - for strategic PR counsel as the Thistle board rejected its 115p-per-share takeover offer.
Brunswick partners Jonathan Glass and Simon Holberton are leading the hostile bid PR plan, reporting to BIL group managing director Arun Amarsi.
Holberton said: 'We are providing strategic communications advice to the BIL board and tactical execution thereof.'
BIL, which already owns a 46 per cent stake in Thistle, is preparing to post its offer document to the hotel chain's investors over the next week.
Meanwhile, Thistle's retained agency The Hogarth Partnership is working on a defence PR strategy.
Hogarth founding partner Nick Denton said the agency is working with Thistle CEO Ian Burke and the group's defence committee.
Thistle - now rumoured to be considering selling off its landmark London hotels for £500m to head off the takeover - rejected BIL's bid as too low. The group said the offer was almost half its net asset value of 211p a share.