I have trawled through the 200 club library and have found the following article, By Richard Meinertzhagen from his memoirs,

In February 1913 on a sheet of water near Meerut I saw eleven peregrines harrying duck who were loath to leave the surface. We were there to shoot, the falcons were there to hunt. The ducks were loath to take wing but were forced to do so by beaters. We co-operated in the ducks discomfiture. It was a beautiful sight seeing the falcons stooping in all directions and paying sant regard to the fusillade. I counted five strikes, all over water and all recovered by the falcons.

Now I cannot confirm if this was a natural flock of peregrine or trained birds?

Keep birding

dave, i love a brave post like this,i,ve been drinking carling and smoking best spainsh golden virginia before anyone ask,s,although it sounds unlikley to see 12 peregrine together I can only ponder why not, from what little i know some birds of prey gather in large numbers on migration and funnel through regular flight paths then disperse to individual
territory to breed,but ho hum i,m sure better informed comment will follow,if it,s in latin i,m out of this.

bravest spelling geoff

Back in about 1970 when ski-ing on Cross Fell, in blizzard conditions, I saw 3 Ptarmigan in winter plumage...there's obviously something about that place!

Back in 1998 while carrying out fieldwork in the Cross Fell area, I saw something that most people refuse to believe. I was hiking out of Dufton and coming up the back of Dufton Pike when I saw 12 Peregrines, mostly juveniles, in one group flying around each other. I watched them for about 5 minutes before a buzzard came past and forced them to scatter. Now at the time I thought they were all juveniles, but I've subsequently convinced myself it was more likely to be two families, two adults and four juveniles in each family. As I say, generally this is treated as a tall tale, people ask what I'd been drinking/smoking etc. But it absolutely definitely happened. So I was just wondering, has anyone else ever seen anything like that, or perhaps has another explanation?