Shamima Begum left UK for Syria when she was 15.

Shamima Begum, the British-born woman who left the country as a teenager to join the ISIS in Syria, on Tuesday launched an appeal against the UK government's move to revoke her citizenship and stop her from returning to London.

Shamima Begum, who was 15 years old when she secretly fled her home in east London in 2015 to join the terror group, is living in a camp run by Kurdish forces in northern Syria.

Now 20-years-old, she is fighting a legal battle to return to the UK and her appeal is being heard at the Special Immigration Appeals Commission (SIAC) this week. High Court judge Elisabeth Laing is expected to consider whether depriving Shamima Begum of her UK citizenship rendered her stateless.

Under UK law, a person can legally have their citizenship revoked but they cannot be made stateless. The UK government maintains that Shamima Begum has access to Bangladeshi dual citizenship through her parents even though the Bangladesh government has since denied any such right.

Tasnime Akunjee, Shamima Begum's lawyer said the arguments for her appeal will centre on her being a rape survivor.

"She was married to a 23-year-old terrorist. Her context is as a rape victim, or a statutory rape victim," he said.

During a four-day preliminary hearing that begins this week, the court will also be asked to consider Shamima Begum being allowed to return to the UK from Syria to give evidence. Her legal team will argue the case cannot be heard without her.

A heavily pregnant Shamima Begum had been found at a Syrian detention camp in February this year. Sajid Javid, then UK home secretary, acted within days to strip her of her British citizenship. Last month, his successor as the home secretary, Priti Patel, also backed that decision and ruled out the prospect of Shamima Begum's return to the UK.