A BARROW submarine has been spotted docking in the port of Gibraltar.

The image of the Barrow-built boat was tweeted this morning by MOD Gibraltar, the official account for British forces in Gibraltar.

Eye-witnesses described "increased security" during the submarine's arrival, and at her berth.

Locals welcomed Torbay's visit, given their long-standing frustrations at the number of incursions into Gibraltar's waters by Spanish vessels.

Yesterday, a Spanish warship was reportedly in Gibraltar waters, and some naval commentators have suggested Torbay's arrival is being seen as a show of force towards the Spanish.

HMS Torbay is one of seven Trafalgar-class boats, which are at various stages of retirement and will be replaced by the Astute submarines.

HMS Trafalgar was decommissioned in 2009, followed by HMS Turbulent in 2012 and HMS Tireless in 2014. HMS Torbay is due to be decommissioned this year followed by HMS Trenchant in 2019, HMS Talent in 2021 and HMS Triumph in 2022.

<blockquote class="twitter-tweet" data-lang="en"><p lang="en" dir="ltr">HMS TORBAY arrives HMNB Gibraltar <a href="https://t.co/rLqDaP03HT">pic.twitter.com/rLqDaP03HT</a></p>— MOD Gibraltar (@MODGibraltar) <a href="https://twitter.com/MODGibraltar/status/869114008250482689">May 29, 2017</a></blockquote> <script async src="//platform.twitter.com/widgets.js" charset="utf-8"></script>