Lawrence studied at Upperthorpe College in Darlington, and the Open University. She moved to Pembrokeshire in the 1970s and learnt Welsh in order to support her children through Welsh medium education.
Lawrence worked for the Trustee Savings Bank and became a member of Dyfed County CouncilPembrokeshire Coast National Park Authority and the PembrokeshirePolice authority. She then became election agent for neighbouring MP Nick Ainger in the 1992 general election and leader of the Labour Group on Pembrokeshire County Council on its formation as a unitary authority before being adopted as Parliamentary candidate for the Preseli Pembrokeshire constituency.
Lawrence was selected to stand for election for Labour through an all-women shortlist, and became MP for Preseli Pembrokeshire in the 1997 election. She was a new Labour loyalist, working on environmental, rural and Welsh language issues. She was a member of the Welsh Affairs Select Committee from 1997 to 2001, and a member of the DTI Department of Trade and Industry Select Committee from 2001 until becoming a Parliamentary Private Secretary at the DTI to Jacqui Smith who was then Minister of State at the DTI. She was Chair of the Welsh Group of Labour MPs at Westminster from 2003 to 2004 and Chair of the Parliamentary All-Party Group for National Parks until leaving Westminster in 2005.
When supporting a government campaign aimed at reducing teenage pregnancy, she revealed that she had given birth to a daughter when she was 17, who was subsequently adopted. She was strongly anti-hunting with dogs and supported legislation to outlaw the practice in the UK.