Morris and Halifax-born Darke, who won time-trial silver on Wednesday, finished one minute 34 seconds behind Marianna Davis of the United States and despite their best efforts to finish together and share bronze, Morris placed third in a photo finish at Brands Hatch. Darke was fourth.
Monica Bascio, another American, was second, 33 seconds behind, before the British duo rode towards the final place on the podium at the end of the 48km race.
“Halfway around the last lap we had dropped everybody else and we knew we weren’t going to catch the Americans and we were safe for bronze,” Morris said.
“We have worked so hard together these last two years we couldn’t bear the thought of crossing the line ahead of each other so we grabbed our hands together 50 metres out and went through the line together.”
Officials denied the opportunity for the pair to share Britain’s 21st cycling medal of the Games – surpassing the 2008 total of 20 – and Morris had to collect bronze alone.
The 33-year-old from Guildford won time-trial gold in Beijing, but was injured and had her bike written off in an accident with a car in July which left her place in London in doubt. She was fifth in the time-trial on Wednesday.
Morris said: “I’ve not had the best lead-in to this Games. This bronze medal means more than gold. It just means everything.”
Darke said: “I’m delighted for Rachel. She so deserves it.
“I had a medal the other day so we both have something to celebrate.”
In the pool, Claire Cashmore was left to reflect on what have been after missing out on Paralympic gold by just three hundredths of a second last night.
Leeds swimmer Cashmore joined Britain’s 4x100m medley relay quartet alongside Heather Frederiksen, Stephanie Millward and Louise Watkin but the world record holders were just edged into silver by Australia while USA completed the podium.
Watkin produced a storming final freestyle leg but she just couldn’t catch Jacqueline Freney on the line as the Australian youngster claimed her eighth gold medal of the Games.
“It was amazing to be on the podium seeing all my friends and family in the crowd, I just wish it was us with that gold medal around our necks,” said Cashmore, who swam the breaststroke leg to keep the home team right in contention.
“It was ridiculously close, it was the length of a fingernail between gold and silver and Australia just managed to touch us off.
“I feel privileged to be part of such an amazing team and it means so much to share that moment on the podium with these girls.”
Cashmore has had a busy schedule with six events entered, five finals reached and three medals won.
However, after also winning silver in the 100m breaststroke and bronze in the 4x100m freestyle relay, the 24-year old is already looking to the future as she seeks to add to her career tally of six Paralympic medals in Rio.
“I hoped to come away with a gold medal but to get two silvers and a bronze is better than I’ve ever done before,” added Cashmore, who will be part of an athletes’ celebration parade in central London on Monday, when hundreds of thousands are expected to line the route.
“There have been a few disappointments along the way but overall I’m really pleased with how the Games have gone for me.
“I’m going to have a rest now and then get back to training. We’ve the World Championships next year, then hopefully the Commonwealth Games and Rio in 2016, which seems a very long way in the distance at the moment. However, I can’t wait to start the whole process again.”
Lucy Shuker and Jordanne Whiley came from a set down to claim a bronze medal in the women’s doubles wheelchair tennis with a marathon 6-7 (8/10) 7-6 (7/2) 6-3 win over Sakhorn Khanthasit and Ratana Techamaneewat.
Britain’s table tennis players took their Games medal tally to a record four when the Class 6-8 trio of Will Bayley, Ross Wilson and Aaron McKibbon – who train in Sheffield – beat Germany 3-0 to clinch men’s team bronze and the women’s pair of Sara Head and Barnsley’s Jane Campbell battled back from two matches down to beat Italy 3-2 and secure Class 1-3 bronze.
In the individual BC1 boccia semi-finals, Britain’s David Smith beat Norway’s Roger Aandalen 5-2 to set up a gold medal match against Thailand’s Pattaya Tadtong.
There was disappointment for Britain’s wheelchair rugby team when a 51-39 defeat against Japan ended their medal hopes, while the women’s wheelchair basketball team finished seventh overall.
The seven-a-side football players were pipped 4-3 by Argentina in their fifth to eighth classification semi-final at Riverbank Arena, and Britain’s men’s sitting volleyball team finished eighth following a 3-0 loss to China.