McLaren are facing the prospect of losing €27million in sponsorship next year with two major brands poised to leave the team after one of the worst seasons in their history.
It is understood that both Johnnie Walker, the whisky brand, and Santander, the banking group, are likely to walk away from McLaren with the team languishing ninth in the constructors' championship.
Johnnie Walker has been with McLaren for a decade, contributing €20m a season.
Its expected departure will be all the more galling for Ron Dennis, the McLaren chairman, given at the end of 2013 they offered to become the team's title sponsor in a €59m-a-year deal.
Dennis turned it down because he believed the offer was too small. A Johnnie Walker spokesman said last night it was in "ongoing conversations" with McLaren but refused to comment on "speculation".
Santander's €7m yearly sponsorship is also set to end.
With McLaren facing a massive loss in prize money due to their poor performance, the additional shortfall in sponsorship revenue could put Jenson Button's career in further jeopardy.
It is not just Button's future which is in doubt. Elsewhere, there are fears that the famous race at Monza will not get a new deal beyond next season.
"There are a few circuits that should never be off the calendar, and this is definitely one of them," Button said.