INTERNATIONALLY renowned academics, business, church and NGO leaders, musicians, artists and performers are being barred from Britain by the UK's "inept", "embarrassing" and discriminatory visitor visa system, it has been claimed.

Critics claim that the UK is now effectively operating a "secret travel ban", applying a blanket bar on visitors that it suspects of might remain in the UK - particularly those from Middle Eastern and African countries – regardless of their circumstances.

"Bizarre" refusal reasons included fully funded academic trips knocked back because it was claimed participants could not support themselves. Others with children or important jobs in their home countries – such as Rev Rola Sleiman, the first woman to be ordained in the Middle East – have been told their applications failed because it was thought they would not return home.

Piksy, a renowned Malawian rapper, received a refusal with the words "insert reason here". Others barred from entry include a Ghanian percussionist who should have performed at the Solas Festival in June, dancers, actors and the crew of Orient Productions in Cairo, due to take part in the Edinburgh fringe's first Arab showcase this year, and Ehsan Addollahi, the Iranian book illustrator due to appear at Edinburgh book festival - though this last decision was reversed following an appeal.

Alison Phipps, Glasgow University's language professor, and UNESCO chair in refugee integration, booked musicians and dancers from Ghana's Noyam African Dance Institute as part of UK-government funded academic project in June but several had their visas refused. Despite the intervention of her MP Carol Monaghan of the SNP, several of the group were unable to travel and she lost thousands of pounds re-booking flights. Her UNESCO colleague Dr Nazmi Al Masri, of the Islamic University of Gaza, was also refused.

Phipps, who in 2012 was awarded an OBE for services to education, said: "Effectively it is now a universal ban on travel from global south countries regardless of whether you are a world leading academic or artist, or a first time traveller on a humanitarian or development project working with UK institutions. We can only surmise that there is a secret travel ban in place now in the Home Office."

She claimed that despite an "outcry over Trump's travel ban" - which has seen the US introduce strict new criteria for visa applicants from six Muslim-majority countries and refugees – "the UK's policy is far worse."

David Hope Jones, director of the Scottish Malawi Partnership, the UK's largest international development network, said problems have been getting progressively worse since 2008. He deals with visa problems every week. "The problems significantly undermines the UK’s power in terms of diplomacy and development," he said. "It doesn’t address the issue of cutting migration – it is inept and inadequate."

He claims the process is “so dehumanising and intrusive” – three months of bank statements even when the trip is fully funded must be provided and many are interrogated at airports – that guests can be put off returning and partnerships with the UK suffer. His organisation, like all who spoke to the Sunday Herald, had never had a visitor abscond and often lost thousands of pounds rebooking flights and accommodation or cancelling high profile events.

Francis McKee, director of Glasgow's Contemporary Arts Centre, agreed that many artists at the top of their field were now unwilling to put themselves through the "humiliating and insulting" process of applying for a UK visitor visa. "Trump's travel ban is explicit," he said. "In our system nothing is clearly stated so decisions can't be challenged and the impact is perhaps worse."

Sara Shaarawi, co-organiser of Edinburgh Fringe's Arab Arts Focus who has been forced to cancelled one show while two others hang in the balance due to visa refusals, added: "It's like something from Kafka. We have toured all over the world. This is not normal."

Carol Findlay of the Church of Scotland's World Mission Council, said she was baffled over decisions to withhold visas for high profile visitors, including Rev Rola Sleiman, the first woman to be ordained in the Middle East, and high profile conference delegates from Hyderabad in Pakistan and South Sudan. "Scotland is known as a welcoming country," she said. "That is undermined when the Border Agency refuses those to whom our partner churches have issued significant invitations."

Patrick Grady, SNP MP for Glasgow North, who was the party's spokesperson on International Development from 2015-2017 claimed fellow politicians had "countless" examples of "inexplicable" visa refusals for visitors particularly Africa and called for an urgent review of the situation.

"There are clearly significant bureaucratic failings in the system – delays in decisions, processing centres hundreds of miles away, sometimes in different countries, from where the application is being made," he added. "There’s an increasing sense that visas, particularly from poorer countries, are declined because the applicant may abscond and therefore harm the Government’s arbitrary and ideological migration target."

A Home Office spokesperson said: "This allegation is completely untrue. All applications, regardless of where they are from, are considered on their individual merits and in line with the Immigration Rules."