Cummings dragged Tony Gallopin (Lotto-Soudal) across with him to the four leaders, and their advantage over the yellow jersey – with Dennis and Dumoulin doing much of the pulling – stretched out towards one minute.
A second chasing group, with Nicolas Roche and King of the Mountains leader Meurisse in tow also looked to come across, but Dumoulin, Dennis and Poels kicked again at the front.
It left Cummings, the virtual leader on the road, with a defensive job to do and it worked to his advantage when Poels – not a threat overall – attacked the other two leaders.
Poels pressed on alone as the road opened out, and the cover from the wind provided by the trees disappeared – pushing on through the crowds and into the final, barriered part of the climb.
Dumoulin and Dennis closed in on the Dutchman, who battled against the gusts but he had enough of an advantage, and enough in the tank, to take the stage.
Dennis and Dumoulin followed six seconds later, both picking up handy bonus seconds, while Cummings came across 20 seconds down – enough to take over the race lead.
Meurisse beat Roche on the line, meanwhile to stretch his mountains lead further and ensure he’ll wear the jersey all the way to the London finale.
Vermote crossed the finish line 1’50” back – his stint in the yellow jersey now over – leaving Cummings in the yellow jersey ahead of the split time trial and circuit race stage in Bristol on stage seven.
Tour of Britain 2016: stage six – result
1) Wout Poels (NED) – Team Sky – 4.56.15hrs
2) Rohan Dennis (AUS) – BMC Racing +6”
3) Tom Dumoulin (NED) – Giant-Alpecin +8”
4) Dylan van Baarle (NED) – Cannondale-Drapac +12”
5) Xandro Meurisse (BEL) – Wanty-Groupe Gobert +16”
6) Nicolas Roche (IRL) – Team Sky – ST
7) Tony Gallopin (FRA) – Lotto-Soudal
8) Steve Cummings (GBR) – Dimension Data +20”
9) Erick Rowsell (GBR) – Madison-Genesis +30”
10) Gorka Izaguirre (ESP) – Movistar – ST
1) Steve Cummings (GBR) – Dimension Data – 27.04.11hrs
2) Tom Dumoulin (NED) – Giant-Alpecin +49”
3) Rohan Dennis (AUS) – BMC Racing +51”
4) Tony Gallopin (FRA) – Lotto-Soudal +53”
5) Dylan van Baarle (NED) – Cannondale-Drapac +57”
6) Xandro Meurisse (BEL) – Wanty-Groupe Gobert +58”
7) Nicolas Roche (IRL) – Team Sky +1.06
8) Ben Swift (GBR) – Team Sky +1.14
9) Jacopo Mosca (ITA) – Trek-Segafredo +1.20
10) Guillaume Martin (FRA) – Wanty-Groupe Gobert +1.24