Hong Kong police said on Tuesday that they have not received any notification from mainland authorities about a locally-based British consulate employee who disappeared earlier this month following a planned trip to Shenzhen.

Asked whether Simon Cheng is in mainland custody at a daily briefing, police officials said they received a missing persons report on August 9, but would not comment on individual cases.

Senior superintendent Kong Wing-cheung added that they have not received any notification from mainland authorities concerning the case under the so-called “reciprocal notification mechanism”.

He said the force’s missing persons unit in Kowloon West is following up on the case.

The British Foreign Office has said they are highly concerned about a media report that the investment officer at the Scottish Development International section of the consulate was detained after he travelled to Shenzhen.

According to reports, he was to attend a business event on August 8 and return on the same day. Hong Kong Immigration Department said it also following up on the report, through the Hong Kong Economic Trade Office in Guangdong.

According to a 2017 agreement, mainland authorities are obliged to notify their Hong Kong counterparts of detentions within seven, 14 or 30 days depending on the seriousness of the crimes.

The new arrangement was meant to ease concerns about the notification mechanism after it came under attack when several Causeway Bay booksellers were detained on the mainland and no information was made available about them for weeks.