Allowing illegal immigrants to stay means the message that you will not be deported gets back to the countries where they came from and the stream of people coming here illegally will never end. It is not fair on all those who apply to come here legally and all people who want to live in the UK must go through the legal system so that we can run the proper checks on people, know who we are letting in and assess there right to be here.
http://www.breitbart.com/london/2017/10/11/illegal-immigrants-unlikely-ever-removed/
Write about these things on social media, write to your MP, support campaigns and do what you can if you agree.