M&C, one of the biggest names in British advertising due in part to its links to the ruling Conservative Party, has so far dismissed the advances of its biggest shareholder, an acquisition vehicle led by software entrepreneur Vin Murria.

But a person familiar with the situation said the two sides were talking, meaning a deadline set by the Takeover Panel is likely to be extended.

Murria's AdvancedAdvT said in January it had floated two options for M&C, one an all-share offer that valued each share at around 220 pence or an alternative structure that includes some cash, valuing them around 200 pence.

That came after an earlier rejection from the board.

The 220 pence price - valuing M&C Saatchi at about 270 million pounds ($367 million) - is based on the AdvancedAdvT stock price when it was halted from trading. The independent directors also rejected that offer. M&C's shares closed at 177 pence on Wednesday.

AdvancedAdvT, which is also backed by private equity group Marwyn, has said it would combine its digital capabilities with the brand recognition of M&C and invest heavily, including through acquisitions, if it takes control.

($1 = 0.7364 pounds)

(Reporting by Kate Holton; Editing by Cynthia Osterman)