I don't think they use pessaries if the waters have broken they use a syntocin (I believe it is called though I may be wrong) drip.
My waters broke on Weds evening 6pm and they wanted to induce me then as I had strep B so there was a higher risk of infection but for most women they wait 48 hours or so to see if full labour starts on it's own. Then they use a drip as they believe that waiting too long for labour to start after waters break can increase the risk of infection in a baby.
I persuaded them to wait until the next day as I didn't want to be induced and wanted to give my body a chance to go into labour on it's own or at least to have a sleep first. This didn't work so I had the induction.
They started it at about 1pm on Thursday and DS was born by 9pm. This was quite quick I think for a first labour as I had been told sometimes it takes a long time especially with the first.
I had a doula (paid female birth partner) with me who was fantastic.
Things to know about drip inductions
Firstly - They can be (not always) be perceived as more painful than normal labours. The contractions are usually full on very quickly. I had very strong contractions 2 minutes apart almost from the beginning for about 7 hours of the labour.
The problem with this is that it is difficult to cope without an epidural and then the epidural can make the labour slower and make the contractions less powerful so they up the amount of syntocin to increase the contractions but the mother can't feel them very well so pushing can be difficult etc.
Secondly - they have to monitor the baby so many women are made to lie down for the whole thing which in itself can slow down labour. It is important to keep moving if you can, insist on it if necessary - I did
In the end I coped with a tens machine and gas and air again with the help of my doula. Without her I would almost certainly have had an epidural which I didn't want as I genuinely believe they can prolong labour and I wanted it over as soon as possible tbh.
The final 2 hours was pushing which was much calmer for me than the preceeding 7 hours.
Overall I think it was fine though as with most I wouldn't say I enjoyed it. The real danger was being steamrollered into a more and more medicalised birth without my real consent. My doula really helped to make sure this this didn't happen.