Under Schedule 7 you may be asked to surrender your passwords. If you do not comply, you risk committing an offence.
However, if you have followed the above steps most of your confidential information will remain private.
If after this there is still confidential or work material on your phone you are allowed to assert confidentiality and officers should cease search.
You may be without your devices for a week, so be prepared for that too.
If you are stopped under Schedule 7, make sure you contact a lawyer and get in touch with CAGE.