Two SAS helicopters have been spotted above Swindon. 

On Tuesday evening, just after 8pm, Swindon and Wiltshire Camera Club member Nick Stinger Nett captured images of two Eurocopter AS365 Dauphin hovering over his house. 

Lisa Hagarty also spotted the aircraft flying overhead while she was walking through the Lawn area.

While it has not been confirmed, the two helicopters are believed to have been participating in a low-flying military exercise taking place above Swindon that was announced via a Civil Aviation Authority (CAA) Notice to Airmen (NOTAM). 

The Dauphin helicopter is an aircraft used by a little-known and rarely-spotted unit 658 Squadron AC (Army Air Corps) in support of the 22nd Special Air Service (22 SAS). 

658 Squadron is based at SAS HQ in Hereford and is part of the Joint Special Forces Aviation Wing (JSFAW) 

The Dauphin helicopters are painted in civilian colours to allow them to blend into normal civilian air traffic. This is to allow members of the SAS to be transported quickly and covertly across the UK. 

These helicopters are also used to fly the SAS into action during counter-terrorism operations. 

Following the notice from the CAA, Darren Carey, an aviation insider who runs an airshow page on Facebook, previously told the Advertiser that understood the training would involve helicopters lowering people onto the rooftops of buildings using ropes. 

These new photos from Nick Stinger Nett do not show people being lowered out of the helicopters, but you can see that one of the helicopter's side doors are open, and there is a framed rig by the door for attaching ropes to. 

The Advertiser now understands that there could be more training in the area but that the current weather is causing them problems. 

The NOTAM indicated residents could expect to see military aircraft between 8pm and 1am from April 8 to April 12. 

A NOTAM is a notice containing information essential to personnel concerned with flight operations but not known far enough in advance to be publicized by other means.

Read More: Closed Debenhams in Swindon used for British army training

The exercise was not advertised on the GOV.UK website which normally advertises low-flying military exercises which could explain the NOTAM being issued. 

This isn't the first time Swindon has been used as the venue for military exercises as the abandoned Debenhams department store was used for training late last year. 

The Ministry of Defence has been contacted for further comment.