Kitchen workers at a popular Cantonese restaurant who are suspected of working there illegally were arrested after a swoop by officials.

Immigration officers and police, wearing body armour, arrested three people as they prepared evening meals at Tam’s Cantonese Cuisine, in Cross Hills.

Two men, aged 36 and 44, and a 27-year-old woman were taken into custody. Another 25-year-old man, who was already reporting to the UK Border Agency, would have his case reviewed, a spokesman said.

All four were Chinese and understood to be failed asylum seekers.

A notice of potential liability was served on their employer, who could be hit with a £40,000 fine — £10,000 for each worker — if found guilty of breaching immigration laws. Last Thursday’s raid started just after 7pm when a team of eight immigration officers and four police ran into the restaurant’s foyer and upstairs to where about five people were eating.

Some officers brought the kitchen staff, who were later arrested, out of the downstairs kitchen and took them upstairs for questioning. They marched them out of the restaurant and into an unmarked van before taking them away. Those held were questioned further and some may be deported.

John Barraclough, of Oakworth, was waiting to eat with his wife, Sarah, and daughter Sophie when the officials raided the restaurant. He said: “We had already ordered our meal and the officers just came in and started looking in the toilets and behind the bar. The next thing we knew, the staff were being interviewed and were then carted off. We were sitting there for more than an hour and still hadn’t eaten.”

A UK Border Agency spokesman warned restaurants it would crack down on those ignoring the rules.

Steve Lamb, regional operations director of the UK Border Agency in the North East, Yorkshire and the Humber, said: “As this successful operation shows, we will act on intelligence to target those businesses that ignore the rules and remove those with no right to be in the UK. There are simple ways of checking a foreign national’s right to work and there is no excuse for not checking the identity of those applying for jobs. We support and encourage employers to comply with the rules but when they fail to do so it is right that we crack down on them.”