End access to the welfare system for anyone who is not a British citizen

I was on holiday in Eastern Europe last summer and had cause to visit a pharmacy. The woman in the pharmacy was very pleasant, aged early 50's and spoke excellent English. We got to chatting and she told me that she intended to go to the UK this year, work for 5 years then claim a full British pension on top of her Bulgarian one. I spoke to some British expats living there, and they were informed that they had to sign a document stating that they would not apply for any social benefits from Bulgaria. Additionally, I was informed that tens of thousands of Macedonians had applied for and received Bulgarian passports last year and I now wonder how many of them are receiving benefits from UK taxpayers and how many citizens of other countries bordering the EU have made similar successful applications

What about all the eastern europeans who come here to have their babies so they can claim child benefit for the child until it is 16 or 18 in full time educatioin. Our hand outs are wide open for abuse!