For years - when the UK was still a member of the European Union (EU) - the number of Zimbabwean officials on the sanctions list had been declining, suggesting a thawing of the relationship.

Only the late long-time leader Robert Mugabe, his family, and the Zimbabwe Defence Industries remained on the EU list.

But now the UK has imposed its own sanctions, reasserting itself and also distinguishing itself from the EU by adopting a more US-like, hardline stance against Zimbabwe.

The US maintains sanctions against almost all government officials including President Emmerson Mnangagwa.

Zimbabwe for years has said the sanctions have contributed to its economic collapse, but others say corruption and mismanagement are to blame.

The southern African nation has successfully lobbied the African Union to support the call to end sanctions and also reportedly spent hundreds of thousands of dollars on hiring public relations groups to patch up its image in the West.

The UK’s latest move is the most significant marker yet of hardening diplomatic relations with Zimbabwe’s three-year-old government.

The four security officers sanctioned are not necessarily Zimbabwe’s most powerful officials, but they are sufficiently senior to send a message to Mr Mnangagwa's government.

Whether the sanctions will have any effect is hugely debatable.

Human rights groups say the abuses seen under Mr Mugabe continue.