Note that if you have an Islamic marriage in the UK, the article suggests that the location of the marriage also matters.
Scotland and Northern Ireland are separate legal jurisdictions and had different requirements for marriage. As per
their website, the imams of the Glasgow Central Mosque are authorised to conduct a marriage that is both religious in nature but also meets the requirements for civil marriage. Similarly, imams registered with Northern Irish Registrar General can conduct religious marriages, which are recognised for legal purposes. So, a nikaah that is also a civil marriage is possible in Scots and Northern Irish law.
To the best of my knowledge, English law (which also applies to Wales) does not provide for such a combined service. English law restricts the location of the marriage ceremony and only marriages conducted at specific licensed places, such as registrar offices and CoE churches, but also tourist hotspots such as the
Palace of Westminster, are considered legal. Some mosques have taken the trouble to get licensed to conduct weddings and such marriages would be recognised under English law.
As an aside, that was allegedly one of the reasons why Prince Charles married Camilla at the Windsor GuildHall and not in Windsor Castle. If he wanted to get married in Windsor Castle, it would have to be licensed for such an event and then it would have to available for anybody wanting to get married there, not just for royal weddings.
Also see this briefing on
non-recognition of Islamic marriages in England and Wales and this
guidance on Muslim marriage and divorce in Britain.
I am not a lawyer or immigration advisor. My statements/comments do not constitute legal advice. E&OE. Please do not PM me for advice.