A statement from the firm says: "The Board of Christian Salvesen notes the recent movement in its share price. The Board confirms that it has received approaches from two parties which may or may not lead to a recommended offer for the Company. The indicative offer proposals received by the Board are subject to a number of pre-conditions.
"The Board is currently continuing discussions and will provide an update to shareholders in due course. There can be no certainty that a formal offer for the Company will be forthcoming or as to the terms on which any offer might be made."

Which begs the question - who's come a-knocking? Speculation, well the Guardian anyway, suggests it's Wincanton, although there seems to be too much overlap between the two firms for that to hold much water, unless Wincanton is chasing volume in a bid to catch up with DHL-Exel. There's the usual long list of candidates, although Kuehne + Nagel appears to be ruling itself out.
However, there is a suggestion that the "two parties" referred to in the statement aren't unrelated, as you might think at first glance, and are in fact two venture capital companies joining forces to share the risk.
Nobody's commenting very much at this stage - so watch this space.

EDIT - We're increasingly hearing that it's Wincanton, a rumour that's strengthened by the firm's rather terse "No comment" when we asked if it was them.
Of course, we could still be wrong.