Association of Professional Political Consultants (APPC)  membership ...access some quite interesting source material

BBC News – UK Politics

BBC - Odd News ...for interest rather than relevance !!

British Chambers of Commerce – Business Policy Unit

Carnegie Europe

CBI – Confederation of British Industry

'Conservativehome'Blog  ...no official connection with the Party but useful conservative commentary and opinion

Defence IQ   commercial publication (UK based); useful if interested in global defence-related issues

Economic & Social Research Council (ESRC)

Institute of Directors – Policy Unit

Institute for Fiscal Studies (IFS)

International Crisis Group (ICG)   reports and commentary; some useful perspectives 

International Monetary Fund (IMF) – UK Pages 

IPSOS-Mori

Legislation.Gov  all the laws of UK, plus those only applying to Scotland, Wales and Northern Ireland

LSE - London School of Economics & Political Science

OECD – Statistics Portal

OECD – UK Pages 

Office of Budget Responsibility (OBR) - Publications  

Overseas development Institute (ODI)  Latest News.  ODI's mandate is to inform policy and practice on international development and humanitarian issues

Political Betting.com

PoliticsHome  all todays politics in one place ..commercial site (paid content but useful free stuff too); not always impartial or objective but interesting & current

Politics UK

Prospect Magazine  well written; reputation for penetrating, unbiased political analysis

ResPublica  multi-disciplinary, non party-political research: analysis of enduring social and economic problems 

The Economist

The Financial Times

The Independent – UK Politics

The Guardian – UK Politics

Thinkpolitics

YouGov.co.uk