I think you'll find that is correct, but it is open to interpretation.
Only police, fire, ambulances and other emergency vehicles are allowed to have coloured lights, but there are a lot of exceptions:
Flashing amber lights are allowed on :
<br style="color: rgb40, 40, 40; font-family: helvetica, arial, sans-serif; font-size: 14px; line-height: 22.3999996185303px;"><br style="color: rgb40, 40, 40; font-family: helvetica, arial, sans-serif; font-size: 14px; line-height: 22.3999996185303px;">a road clearance vehicle
<br style="color: rgb40, 40, 40; font-family: helvetica, arial, sans-serif; font-size: 14px; line-height: 22.3999996185303px;">a bin lorry
<br style="color: rgb40, 40, 40; font-family: helvetica, arial, sans-serif; font-size: 14px; line-height: 22.3999996185303px;">a breakdown vehicle
<br style="color: rgb40, 40, 40; font-family: helvetica, arial, sans-serif; font-size: 14px; line-height: 22.3999996185303px;">a vehicle with a 25 mph top speed
<br style="color: rgb40, 40, 40; font-family: helvetica, arial, sans-serif; font-size: 14px; line-height: 22.3999996185303px;">a vehicle wider than 2.9 metres
<br style="color: rgb40, 40, 40; font-family: helvetica, arial, sans-serif; font-size: 14px; line-height: 22.3999996185303px;">a roadworks vehicle
<br style="color: rgb40, 40, 40; font-family: helvetica, arial, sans-serif; font-size: 14px; line-height: 22.3999996185303px;">an escort vehicle
<br style="color: rgb40, 40, 40; font-family: helvetica, arial, sans-serif; font-size: 14px; line-height: 22.3999996185303px;">a Revenue and Customs vehicle
<br style="color: rgb40, 40, 40; font-family: helvetica, arial, sans-serif; font-size: 14px; line-height: 22.3999996185303px;">a surveying vehicle
<br style="color: rgb40, 40, 40; font-family: helvetica, arial, sans-serif; font-size: 14px; line-height: 22.3999996185303px;">a clamping or tow truck vehicle
<br style="color: rgb40, 40, 40; font-family: helvetica, arial, sans-serif; font-size: 14px; line-height: 22.3999996185303px;">airport vehicles
<br style="color: rgb40, 40, 40; font-family: helvetica, arial, sans-serif; font-size: 14px; line-height: 22.3999996185303px;">any other specially authorised vehicle
....and so on.
It sounds silly but I'd check with the local police or highways.
NB: Here's some light reading for you (pun intended
):
http://www.legislation.gov.uk/uksi/1989/1796/made
PS: I must admit I've seen dozens of HGVs with fairly large trees adorned with coloured lights.
Edited by: allan40alt