Packages sent through the post

The NCA, which leads the UK’s fight against serious and organised crime, said in its recently-published annual report: “Firearms, components and indicative parts often seized in fast parcels and post are frequently acquired through the Internet.

“While firearms make up a small proportion of commodities sold via the Dark Web (with drugs being the majority), there is increasing evidence that it is an avenue for individuals without previous criminal contacts to acquire them, using virtual currencies such as Bitcoin.”

The Royal Mail would not disclose its policy on parcel checks when asked for security reasons.

However, the Royal Mail says while it encourages employees to report suspicious-looking packages, major seizures often rely on intelligence being shared with its depots.

A spokesman said: “If enforcement agencies have specific intelligence about illegal firearms in the mail, we work in partnership with them, giving them access to suspicious mail where appropriate.

“Border Force personnel are stationed at our major international operations.

“We consult Home Office approved experts who help us to identify illegal firearms once a suspect item has been flagged in the mail by X-ray or other means.

“When an illegal weapon is confirmed, it is handed over to the law enforcement agencies to take appropriate action.”