Observer report suggests supermarket giant pushes the system to the limit. Plus, a round-up of the weekend's other stories.

Does supermarket giant Tesco have Britain’s planning system in its pocket, asks the Observer in its business pages. The paper reports that Tesco, in its bid to retain its position as the country’s most powerful retailer, routinely pushes the planning system to breaking point. Tesco’s “overweening arrogance” includes, according to the paper, attempting to build stores on land not zoned for retail development, taking councils to costly appeals, building larger stores than allowed and then retrospectively applying for new permissions.

More business news with the Financial Times reporting on Saturday that ACS, Spain's largest construction and services group, yesterday beat a strong field of contenders by agreeing to pay €2.22bn for Banco Santander's controlling 22% stake in Union Fenosa, the country's third largest electricity generator.

It’s not such good news for motorists, according to the Sunday Times. The Department for Transport is considering introducing a road toll of up to £20 for motorists travelling to and from London on the M4, in a bid to cut pollution around the extended Heathrow airport. The newspaper claims it has seen an internal memo from transport department officials detailing the plans, which would clear one of the hurdles for construction of a third runway at the airport by ensuring stringent European emissions targets are met.