The company, which has about 20 shopping centres across the UK and Spain, said it sought an extension from the UK takeover panel to the earlier Nov. 1 deadline as the consortium wanted to continue discussions.
London-listed Intu said on Oct 19 it was considering a preliminary takeover offer from a consortium led by Whittaker for 215 pence per share, a premium of nearly 21 percent to the stock's closing price the day before.
The proposed deal, backed by Saudi Arabia's Olayan Group and Canadian property investor Brookfield Asset Management, valued the FTSE 250 firm which owns Manchester's Trafford Centre at 2.91 billion pounds ($3.8 billion).
The news sent shares of the company 14 percent higher on the day.
The Whittaker-led consortium initially offered 205 pence per Intu share on Oct. 11. Olayan and Whittaker's Peel Group already hold 29.9 percent of Intu.
Earlier this year, larger rival Hammerson made and eventually dropped an offer of 253.9 pence per share for Intu, which has been hit by the downturn in British bricks-and-mortar retailing seen many high street stalwarts go bust.
Last week, Intu cut its full-year like-for-like net rental income growth forecast, citing the impact of this year's failure of a number of tenant businesses including House of Fraser.
To offset the hit, the company had then said it was looking to use some of its available land to build houses and hotels around its shopping centres.
Shares of the company were down a little over a percent at 195.56 pence at 0810 GMT.
(Reporting by Arathy S Nair in Bengaluru; Editing by Bernard Orr and Sunil Nair)