The 'cavalcade' on Saturday travelled from Heatherwood Hospital, Ascot - site of the current minor injuries unit - to the Bracknell Clinic at Brants Bridge, where the new urgent care centre (UCC) is to be established.
The establishment of the UCC is one of three changes to healthcare services approved by the now defunct NHS Berkshire PCT in March, which also included permanently closing the Ascot Birth Centre, the rehabilitation ward, with more beds at Wexham Park in Slough plus services in the community. Terry Pearce, from campaign group Defend Our Community Services (DOCS), said: "Through the cavalcade, we wanted to explain that it's not easy for people living on the other side of Ascot.
"The authorities at the Bracknell Clinic seemed a bit panicked, because they locked the gates, with us inside the car park. They realised they were stopping ambulances from coming in.
"We had no intention of entering the clinic. The last thing we wanted to do was cause problems with patients or staff. Our presence there was symbolic."
"The staff at Heatherwood are familiar with us from our protests there. We never go inside. In the end they [Bracknell Clinic's managers] agreed we could stay there. After amicable negotiations with the security at Brants Bridge, they opened up the gates, letting the ambulances in and us out."
The cavalcade followed a protest march of about 100 people from Ascot High Street to Heatherwood Hospital, with marchers holding a banner, displaying the words 'Over 25,000 said keep Heatherwood and all its services' - referring to a petition that collected thousands of signatures to retain services at the hospital.
Spike Humphrey, of Ascot Community Action Group for Heatherwood said: "Despite the rain we had people who had been on previous marches and some new people. Marches like this help keep the issue in the public eye. We've made it clear that we are not going away. We are carrying on with the campaign.
"We reject the decision by the PCT and we are going to fight against it.
"We encourage people to come along to the Royal Borough meeting at Ascot Racecourse on May 9."
Joe Wise, public relations manager of the Royal Berkshire NHS Foundation Trust, which owns the Bracknell Clinic, said security staff at the clinic closed the gates after they noticed a large number of vehicles coming through them.
Once the protestors explained their intentions, they were allowed in.
He said: "They had no idea who these people were or what they were going to be doing. The trust wasn't told they were planning a demonstration.
"They closed the gates to stop any more coming in."
The Royal Borough has a petition on its website which has already amassed more than 2,500 signatures. The council is also organising a special meeting on Thursday, May 9, at 7.30pm in The Pavilion at Ascot Racecourse.