Book excerpt: Trust in our politicians is at an all-time low. We're in a "post-truth" era, where feelings trump facts, and where brazen rhetoric beats honesty. But do politicians lie more than they used to? And do we even want them to tell the truth? In a history full of wit and political acumen, Private Eye journalist Adam Macqueen dissects the gripping stories of the biggest political lies of the last half century, from the Profumo affair to Blair's WMDs to Boris Johnson's £350 million for the NHS. Covering lesser known whoppers, infamous lies from foreign shores ("I did not have sexual relations with that woman"), and some of the resolute untruths from Donald Trump's explosive presidential campaign, this is the quintessential guide to dishonesty from our leaders - and the often pernicious relationship between parliament and the media. But this book is also so much more. It explains how in the space of a lifetime we have gone from the implicit assumption that our rulers have our best interests at heart, to assuming the worst even when - in the majority of cases - politicians are actually doing their best.