A hooded man burst into a busy McDonald’s restaurant and sprayed suspected CS gas in the air – leaving customers short of breath and coughing uncontrollably.

Six ambulances and three fire engines were called to Dudley Street in Wolverhampton city centre after the man ran in and sprayed a mystery chemical.

The branch was evacuated and 18 customers, including children, teenagers and pensioners, who were overcome by the fumes were quarantined inside neighbouring Game store while they were checked by paramedics.

Some complained of a “burning sensation” in their throats which left them struggling to speak while others had tears streaming down their face.

Police were today checking CCTV footage and said there was no evidence to suggest the drama, which happened at 3pm yesterday and closed the restaurant for two hours, was a targeted attack on any particular customers.

Diners told how a man “ran in and sprayed something in the air”, causing the panic.

Ambulance staff set up a temporary medical station in Dudley Street for staff and customers to have their pulse and blood pressure taken, but nobody needed hospital treatment.

Cath and Tony Sankey, from Willenhall, were eating in the restaurant at the time and described the experience as “shocking”.

“I went to get drink and ice cream and found I had a burning sensation in my throat and couldn’t speak to complete my order,” said Mr Sankey, aged 64.

“People were coughing uncontrollably and then a member of staff cleared everybody out and we were told somebody had run in and sprayed something.”

Mrs Sankey, aged 65, added: “I just felt shocked to be honest because you just don’t expect something like that to happen – it was quite frightening.” Scores of shoppers and city centre workers stopped to watch as both McDonald’s and and Game were evacuated.

Onlooker Darren Atkinson, a shop assistant at Phones4U opposite McDonald’s, said: “All these ambulances and fire engines suddenly turned up and people were being rushed out of McDonald’s. It was scary because you’re left wondering if there’s been a bomb scare or if anyone’s been hurt.” Inspector John Smith, of West Midlands Police, said today atmosphere readings were taken in the restaurant and surrounding shops but had revealed nothing about the identity of the mystery gas.

It is believed one explanation is the chemical may have been CS gas but police today played down the incident.

Insp Smith added: “We have checked CCTV footage and there is nothing to suggest this was a deliberate, criminal or malicious attack. The premises were evacuated in line with standard procedures, and investigations are ongoing.”

Everyone exposed to the gas was given advice from paramedics on what to do if their health worsens before being allowed home. The restaurant was open today as normal.