Budweiser brewer Anheuser-Busch InBev has again sweetened its offer as it bids to takeover Peroni and Grolsch rival SABMiller, in a deal valued at £70 billion.

Belgium-based AB InBev said it now plans to offer £43.50 a share for the business, making it the largest attempted takeover of a British firm in corporate history.

It added its offer for SABMiller represents a premium of around 48 per cent to SABMiller's undisturbed closing share price last month.

The SABMiller board previously turned down £42.15 a share, and two other earlier offers for the firm, saying they all substantially undervalued the business.

On Wednesday under UK Takeover Panel rules AB InBev must table a firm bid for SABMiller, or walk away for six months.

AB InBev last week urged SABMiller shareholders to force its board into serious takeover talks, after the rival brewer rejected its latest offer for the business.

Carlos Brito, chief executive of AB InBev, said last week: ''Notwithstanding our good faith efforts, the board of SABMiller has refused to meaningfully engage with us."

But SABMiller chairman Jan du Plessis has called his firm the ''crown jewel of the global brewing industry''.

A tie-up between the two would create a global beer giant worth more than £180 billion.

AB InBev is the world's biggest beer business, while SABMiller is the global number two.

Brewer AB InBev has a stable of more than 200 beers, including Corona, Beck's, Leffe and Hoegaarden.

SABMiller has brands such as Miller, Foster's, Coors and Bulmers cider. It employs around 69,000 people in more than 80 countries and has global annual sales of more than $26bn (£17bn).

Its suitor AB InBev has a 155,000-strong global workforce and makes more than $47.1bn (£30.5bn) in global revenues.

SABMiller attempted to acquire rival Heineken a year ago, but its advances were rebuffed.