Chinwe Azubuike had not seen her Nigerian family for 14 years when she invited them to her marriage in London to Ed Cross, the art-dealer father of her two British-born children.

As a member of the Igbo tribe, it was particularly important to the pregnant bride that her mother, siblings, niece and nephew were there to perform the traditional ceremony in March.

“As a Nigerian and the first daughter of my family, great prestige is attached to us on our wedding days because of the traditional ceremony that is performed,” Azubuike said. “I had always imagined a proper Nigerian-styled wedding: colourful and exciting, with all my family present. It would have been a great honour to have my siblings at my wedding.”

But despite Azubuike employing an immigration specialist to prepare and submit all seven applications on behalf of her family, all of her four siblings, niece and nephew were refused permission for the nine-day visit – even though one of her sisters has travelled to the UK several times before.

“When we received the decisions refusing my siblings’ and niece’s visitor visa, I was devastated,” said Azuibuike, a student at the School of Oriental and African Studies (Soas) at the University in London. “Words cannot express my feelings. I really tried to be courageous about the whole agonising episode but it was a one-time event in my life and I cannot explain the huge disappointment I felt. The Home Office’s refusal killed my spirit.

“I cannot turn back the hand of time to celebrate my wedding again,” she added. “My wedding day remains one of the most memorable things in my life. But it also makes me remember how lonely I felt deep inside. I am the only member of my family living in the UK and none of my siblings were there with me.”

The family’s lawyer, Jan Doerfel, said the reasons the Home Office gave for the refusals were “unlawful, spurious and plainly wrong”.

“The entry clearance officers (ECOs) taking the decisions on the applications persistently and unlawfully ignored the fact that Chinwe and Ed had committed to paying all her siblings’ expenses, had proved they had sufficient funds to do so (in the region of £39,000) and had booked holiday accommodation for the nine-day visit,” said Doerful.

“Instead, the ECOs perversely held that the siblings did not ‘have sufficient funds available’ by focusing on the siblings’ own income to the exclusion of their sister’s financial support. This is unlawful under the immigration rules which expressly allow reliance on third-party support. In one brother’s case, the ECO even alleged that because he had to rely on third-party support, and could not pay for the expenses himself, this meant he had no intention to return.”

Doerfel added that: “Even though all family members live together in one family home which they own and have lived in all their lives, and are employed in stable jobs or self-employed and even own a plot of land in Nigeria which they have plans to develop, the ECOs refused their application on the basis that they do not have ‘sufficiently strong family, social or economic ties’ in Nigeria. As a result, they accused them of not being genuine visitors and having no intention to leave the UK at the end of their visit. Even though the clear and compelling purpose for the nine-day visit was the wedding, the ECOs unlawfully and persistently ignored this reason.

“To add insult to injury, two applications were refused because the ECO had misread their application forms and wrongly assumed that their stated yearly income was monthly – even though the pre-printed visitor’s application form requests yearly income – and, as a result, accused them of lying about their economic circumstances.”

Doerfel has lodged judicial reviews for two of the siblings whose visas were denied. The other siblings have submitted complaints to the Home Office and are asking for a reversal of the entry clearance decisions, an apology and compensation for financial costs incurred.

• This article was amended on 6 July 2017. The name of Chinwe Azubuike’s husband is Ed Cross, not Ed Cook as originally stated.

