High Speed 2 is controversial, over budget and part-cancelled, but its Colne Valley Viaduct is a 2024 Fine Art Commission Trust’s Building Beauty award winner. On the walk we can assess whether it is beautiful, hideous, or hidden. From Denham station we cross Buckinghamshire Golf Club to the Grand Union Canal Walk, then head north on the Colne Valley trail, passing under the Chiltern Line's 1850s brick arch viaduct and the iconic view of the new viaduct crossing water. We continue on the London Loop to Harefield and St Mary's Church, then see the viaduct from above on the Hillingdon Trail. After picnic or lunch at the Coy Carp pub, we recross the valley, pass under the viaduct again where it crosses the road, and then return to Denham past the Aerodrome.
Train: 10:10 from Marylebone arrives Denham 10:39. Buy return to Denham. Freedom Pass holders buy return from West Ruislip.
Lunch: pub or picnic by the Grand Union Canal.
Toilet: use toilets on train: Denham station toilets open only to noon IF WORKING, and then at lunch.