Some drivers experienced problems after filling up their cars at Tesco's Eastville station in Bristol.Read more
Several vehicles could have been filled with the wrong type of fuel after a mix-up at a Tesco petrol station.
In a video posted on Facebook one motorist, Safoor Malik, warned drivers away from Eastville station in Bristol.
He said: "They have mixed diesel with petrol in the pumps. Four cars are broken down, God knows how many more."
Tesco said it had temporarily closed the station for an investigation.
French supermarket chain Casino, whose shares have hit by concerns over its debts, said it had rejected an approach from domestic rival Carrefour, according to a Reuters report.
Casino said it had been contacted by Carrefour in recent days over a possible tie-up, but said there were regulatory barriers to any deal, given the dominance of the two companies in the French domestic supermarket sector.
“The board unanimously reiterated its entire confidence in Casino’s strategy for value creation based on its unique market positioning,” Casino said in a statement.
It added: "The board unanimously decided to reject Carrefour’s approach."
Earlier this year, Carrefour announced a strategic alliance with Tesco.
Tesco's toe in the discounter water - Jack's - will "need to work hard to dent the success of Aldi and Lidl" says retail expert Dr Gordon Fletcher from the University of Salford.
"The new Jack's brand – a reference to Tesco founder Sir Jack Cohen and a nod to the company’s 100-year history – will begin appearing next week in repurposed and existing Tesco properties," he says.
"The challenge for Tesco will be to continuously compete at an unfamiliar price point on common household products.
"Aldi and Lidl both successfully compete in the retail sector by using a consistent layout in custom-built stores with a supply chain that sources items from suppliers across Europe."
The UK's biggest supermarket chain is taking on Aldi and Lidl with its own discount store, Jack's.
More Jack's reaction, this time from Fraser McKevitt, head of retail and consumer insight at Kantar Worldpanel.
"Jack’s isn’t going to make an immediate dent in the competition’s market share - not at the rate of openings announced today.
"For context, there are already over 1,300 Aldi and Lidl stores across the country and the two have a combined market share of 13.1%, so Jack’s is clearly playing a longer-term game."
Supermarket group Tesco launches the first outlet of its discount Jack's chain.
BBC Radio 4
More from retail analyst Natalie Berg, speaking about Jack's on the Today programme.
"As a discount chain there are going to be some guaranteed aspects," she says.
"The stores will be smaller, with a limited assortment of products, say 1,000 rather than 30,000 in a big Tesco."
She the majority of the products for sale will be own-label, and sold in the "stripped-down environment" familiar to shoppers at Aldi and Lidl.
BBC Radio 4
Tesco are going to have its work cut out if it is to make its new discount chain Jack's a successful competitor to low-cost German outlets Aldi and Lidl.
"The odds are against them," retail analyst Natalie Berg tells Radio Four's Today programme.
"If you look at the attempts by Sainsbury's and Asda in the past, it is hard to run something like this alongside your major supermarkets.
"They will have to undercut Aldi and Lidl on prices," she adds, while warning that Tesco will need to be wary of cannibalising its current shopper base.