The first thing I would do would be to join a Trade Union - or speak to your union rep if you are already a member. There is an interactive tool on the TUC site to help find one that is suitable. Remember, the HR team at work is there to protect the business, not the employees.
Secondly, she should start documenting events as they happen. It's easier with emails than with conversations. There's nothing wrong or illegal about recording a call or conversation with your phone.
This is important because she needs to be able to demonstrate objective facts - not just "I sometimes feel that..." She needs to be able to say "On Thursday at 11:22 he said..."
Thirdly, if at all possible, she should address this with her manager. Some people don't understand the power their words and actions have. Simply saying "I don't think that's a professional way to behave in the workpace" or "When you shout at me - I don't perform at my best" can work.
Fourthly, speak to his manager or your HR team. They will almost certainly have processes in place to deal with abusive staff. Make sure that she has evidence - or at least co-workers who are also willing to back her up.
Finally, yes, there are laws against bullying and harassment in the workplace - assuming it's related to
- gender (including gender reassignment)
- marriage and civil partnership
- pregnancy and maternity
- religion or belief
- sexual orientation
Best of luck - and I hope the situation can be resolved.