A former Christian who converted to Islam has been sentenced to imprisonment in the United Kingdom after he attempted to join the terror group Islamic State (ISIS).

Thirty-year-old Gabriel Rasmus, who comes from a Christian family from Chain Walk, Lozells, Birmingham before converting to Islam in 2008, is facing a jail term of four years and three months, after he admitted to preparing for terrorist acts.

He also admitted that he had the "option" of launching a terrorist attack in the United Kingdom if he stayed longer in the country. He told the court if he had to "stay in this country he would commit some terrorist attack here."

"I think I've been portrayed as some crazy jihadi evil guy," Rasmus was quoted by the Premier website as saying.

He also expressed admiration towards the brothers Said and Cherif Kouachi, who conducted the bloody attack on the offices of French satirical newspaper "Charlie Hebdo" in Paris, which killed 12 people and injured 11 others. Rasmus said the brothers "did a good job."

Rasmus also planned to travel to Syria and "join forces with Islamic State to offer their services together with their lives if need be," prosecutor Karen Robinson said.

According to a separate report from Kent Online, Rasmus purchased several outdoor equipment in preparation for his flight to the Middle East to join the ISIS — including walking boots, a night scope telescope, compass, head torch, a route planner, vitamins and a thermal flask.

"As part of this investigation, extensive surveillance and undercover activity was used. They were unknowingly being monitored by our officers who swooped as they attempted to leave the port," acting chief constable Marcus Beale, counter terrorism lead for West Midlands Police, told Kent Online.

"We will use every lawful technique and power available to us to prevent people from travelling to Syria," he added.

The Christian convert to Islam was arrested with two other men while hiding inside a truck at the Kent port of Dover in April 2015. These are Anas Abdalla, who was sentenced to five years in jail, and Mahamuud Diini, who was found not guilty earlier this year.