Short airfield closure 4-May-23?

[IMarsh]

Found this NOTAM which appears to effectively close the airfield for 20 minutes early this evening. Any ideas?

U2905/23 - AIRFIELD EMBARGO.
NATIONAL POLICE AIR SERVICE AND THAMES VALLEY AIR AMBULANCE WOULD
BE REQUESTED NOT TO FLY UNLESS OPERATIONAL,
IF REQUIRED, THIS WOULD BE TACTICALLY DECONFLICTED BY ATC
FOR A NORTHERLY DEPARTURE. 04 MAY 17:50 2023 UNTIL 04 MAY 18:10 2023. CREATED:
03 MAY 12:51 2023

[roger4]

There is very occasionally a Spitfire or Hurrican doing aeros over Benson, early evening. I believe these are associated with formal dinners. Maybe another one tonight?

[roger4]

Other than the Police heli arriving back into Benson from the north-east, the only other activity during the Notam-ed period was a low fly-through by based Chinok ZA671 (as "Vortex 250").

[WE.177]

From RAF Benson’s Facebook page:

Last night we celebrated His Majesty The King’s Coronation with a sunset ceremony followed by a Dining in Night in the Officers’ Mess. All ranks, junior to senior were invited, joined by guest of honour Group Captain (Retired) Philip Pinney.

Group Captain Pinney reflected on his time as Station Commander RAF Benson, but also as flying instructor to His Majesty The King. The then Squadron Leader Pinney spent two and a half years teaching him to fly the Royal Chipmunk, amassing over 180 sorties. A historic and memorable occasion for all.

One of the photos shows a Chinook doing a fly-over.

[roger4]

Thanks, that explains it perfectly!