A group of 13 have voiced their outrage after an 11-night break to Tunisia was 'completely ruined' when several members of their party became violently ill.

Keith Knight, 67, from Sheffield, was staying at Club Omar Khayam in Hammenet, with 12 friends and family members when he and several others were struck down with symptoms of gastric illness just days into their trip.

On the fourth day of the holiday, which was booked through Thomson tour operator TUI UK Limited trading as SkyTours, Knight began suffering with chronic diarrhoea, stomach cramps and loss of appetite.

Family claim that majority of the large group suffered from gastric illness symptoms over the 11-night period

He claimed that his symptoms continued throughout the entire holiday and made it difficult for him to leave the room or relax.

On his return to the UK, the 67-year-old visited his local GP, where he was told he had contracted salmonella.

Wife, Margaret, 71, began experiencing similar symptoms to her husband a few days after he fell ill.

The couple claim that the majority of the large group suffered from gastric illness symptoms over the 11-night period.

Jane Hollingworth, 48, another family member travelling with her daughter Kelly-Jay Ahmed, 17, both experienced gastric illness and described the conditions at the hotel as 'unsanitary'.

Hollingworth claimed that the hotel in general was 'unclean', and on one occasion she reportedly saw faeces in the hotel swimming pool, which saw holidaymakers asked to vacate the water for an hour while staff removed the excrement with a net.

She also reported that tables in the restaurant were left dirty, cutlery and glassware was often stained and the hot food was served lukewarm on occasion.

The 48-year-old also claimed that flies were seen on and around the food on a number of occasions.

Mr Knight, a retired mechanic, said: 'The whole experience was extremely distressing for myself, my wife and the rest of my family and friends.

'My symptoms continued throughout my stay and some of the group who also became ill continued to suffer even after coming back. It really is the last thing you expect when you go on holiday.

Keith Knight, 67, from Sheffield, was staying in Hammenet, with 12 friends and family members when he and several others were struck down with symptoms of gastric illness just days into their trip

'My wife Margaret complained to the TUI representative about our illnesses and the food while on holiday but she told us nothing could be done and to complain on our return to the UK.

'Since returning to the UK Margaret telephoned the tour operator to complain and advise that one of the party was suspected to be suffering with Salmonella.'

'We are now hopeful that [we will get] the answers we feel we deserve about the terrible illness we suffered.'

Clare Pearson, a specialist travel illness lawyer at Irwin Mitchell, representing the family, said: 'This large family holiday was completely ruined by illness which has led to them to come to us to help them get the answers they deserve about what caused them to fall so ill.

'Illnesses of this nature are very serious and can, in some cases, lead to long-term impacts, or even fatalities.

'The immediate priority now is ensuring anyone affected receives the help and support they need, as well as identifying the cause of the illness as soon as possible.

'As we conduct our investigations we ask anyone who has stayed at the Club Omar Khayam and may be able to help provide information about the conditions, to get in contact with us as they may be able to help with our enquiries.'

Speaking to MailOnline Travel, a spokesperson for SkyTours said: 'We are sorry to hear of Mr and Mrs Knight's experience at Club Omar Khayam in Hammamet, Tunisia.

'As we understand this is now subject to legal proceedings, it would be inappropriate for us to comment further.