LONDON, Nov 29 (Reuters) - Shares in BT jumped as much as 9% on Monday before sliding back, after India's Reliance Industries denied a media report it was weighing a bid for the British telecoms group.

The Economic Times said billionaire Mukesh Ambani's Reliance might make an unsolicited offer to buy into BT or try to get a controlling share, citing sources familiar with the matter.

It said Reliance could also partner with BT's networks arm Openreach and fund its fibre expansion plans.

But Reliance dismissed the report in a stock exchange filing, saying: "We categorically deny any intent to bid for the UK telecoms group BT. The article is completely speculative and baseless."

In earlier trading, BT's shares had risen as much as 9%. They were up 5.7% at 1027 GMT, following Reliance's statement. Reliance was up 1.2% at 2,441 rupees.

The British company, whose shares have more than halved in the last five years, was already the subject of takeover speculation after Franco-Israeli billionaire Patrick Drahi bought a 12.1% stake this year.

Drahi will be free to buy more of the British telecoms giant on Dec. 11, having pledged in June he wouldn't launch a takeover offer for the company - a statement that precluded him from doing so for six months under British takeover rules.

($1 = 0.7500 pounds) (Reporting by Paul Sandle; Editing by Kate Holton and Edmund Blair)