Customers at McDonalds will be able to order a Big Mac and wi-fi under a deal announced yesterday between the fast food chain and BT that is designed to get diners on the net while they eat.

The telecommunications company is installing equipment that allows customers with a laptop computer to access the internet without wires in 500 McDonald's outlets across the UK.

BT intends to aggressively push the benefits of public access to broadband without wires - or wi-fi - this year. There are already 1,700 locations across the country, from train stations to pubs, where customers can log on with a subscription to BT's Openzone product. BT has plans to have a total of 4,000 so-called wi-fi hotspots by the summer.

But BT has so far provided little information about how many people are using the service. Many new laptops have the technology to access wi-fi built-in, but anecdotal evidence suggests consumers have been slow to surf using their own kit while in public. All BT will say is that it has 100 corporate customers signed up to its wi-fi product.

At first glance the deal looked a little surprising, as the equipment will be installed first in McDonald's drive-through outlets, raising the prospect of customers try ing to order, their food, collect it and log on at the same time.

But a BT spokesman explained that the range of the wi-fi signal means customers will be able to park in the McDonalds car park and log on from their cars. Logging on from the safety of their cars eliminates one of the main barriers to the use of wi-fi - fear of taking out expensive computer equipment in public.

"These drive-through sites get a lot of on the road business people such as sales reps coming through," he said. Widening the wi-fi signal range to include car parks means "it's not as daft an idea as it might at first appear", he added. The "hotspots" will be up and running by the end of March.