Hong Kong’s high-speed rail link to the mainland will proceed to a trial operation stage next month with the HK$84.4 billion (US$10.7 billion) project ready for opening in September pending final approval of a controversial joint checkpoint plan.

Speaking at a work completion ceremony at the West Kowloon terminal on Friday, Chief Executive Carrie Lam Cheng Yuet-ngor called on the Legislative Council to pass the joint checkpoint bill as soon as possible.

“Today’s an important milestone for the high-speed rail project as it is now 99 per cent complete … I tried it out myself and it only took eight minutes travelling from Shek Kong Stabling Sidings to here in West Kowloon,” she said.

“Now it’s only one step away from our target of opening the high-speed rail in September – local legislation of its joint checkpoint facility. I hope all lawmakers will adopt a pragmatic approach in scrutinising the bill so the co-location arrangement can be passed very soon,” she said.

Under the bill, the West Kowloon terminal for the line will house a facility for both local and mainland authorities to carry out immigration and customs procedures.

A designated area, including two office floors, waiting hall for departing passengers, station platforms and connecting passageways and escalators, as well as the compartments of the trains, will be subject to the jurisdiction and laws of mainland China.

In December, the National People’s Congress Standing Committee, China’s top legislative body, approved the plan. But the Hong Kong Bar Association soon after said it was “appalled” by the decision and believed it to be in breach of the Basic Law, Hong Kong’s mini-constitution.

It argued that Legco had no authority to enact a law that contravened the Basic Law.

MTR Corporation’s chairman Frederick Ma Si-hang said the express rail link would undergo tests from next month, including checks on its various control systems, gates, and ticketing and signal systems.

He also revealed the results of a naming competition. Out of 16,000 entries, the judging panel selected “Vibrant Express” as the name for the nine Hong Kong-owned trains, and this would be shown on their livery when they entered service.

At a Legco bills committee meeting on Friday, Secretary for Transport and Housing Frank Chan Fan said he was still discussing with mainland authorities how much rent and land development fees the Hong Kong government would impose for the lease of the mainland port area in the West Kowloon terminal.

Under a similar arrangement at Shenzhen Bay Port, the Hong Kong government pays around HK$8 million per year in rent to run the Hong Kong port area for border checks, and it paid HK$4.2 billion for construction and land development.