Looking for lists of passengers

I am looking for some help to find information regarding Irish people who left Ireland and went to the UK around 1850's

Also if anyone could help me also find lists of Irish passengers that left the UK around 1850's I appreciate it so much.

I know RootsIreland has access to lists of passengers however when I consult there, it says there are no records so if anyone knows another website I can check, you would help me a lot!