Pointless and dangerous

Last Sunday around 10.00 at night taking my daughter to Ashford. There was very little traffic. At the point where operation Brock started the motorway went to a single lane and 30mph speed limit. All the traffic condensed into a slow moving queue. No apparent reason for this, misleading signage ('CHECKPOINT AHEAD'). No where to stop for a rest or if there was a breakdown. Was between two lorries the whole way. Just awful.