HAVE you seen any ghosts recently?

If you've been watching River, the BBC's excellent new crime drama, you will have been spoiled (or should that be spooked) for choice. Swedish actor Stellan Skarsgård plays troubled detective John River, who sees ghosts at every turn, including his deceased colleague Stevie (played by Nicola Walker). As the series unfolds, we learn that River has mental health problems, but has kept them secret so as not to jeopardise his career.

Meanwhile, the ghost of Banquo has risen again, in the new blood-soaked adaptation of Macbeth which hit cinema screens this month. Michael Fassbender plays the Scottish warrior-who-would-be-king and offers a new take on Shakespeare's fallen hero. In this 21st-century version, a bloodied and battle-weary Macbeth is suffering from post-traumatic stress. The appearance of Banquo's ghost at the court's banquet is the surest indication of the decline of Macbeth's mental wellbeing.

It's Hallowe'en tomorrow - so you might well see some ghosts around. Most likely they will be youngsters dressed up for freaky fun rather than the real deal. But you never know - York prides itself as being one of the most haunted cities in Europe with more than 500 "hauntings" recorded within the city walls.

Whether you are a believer or not, ghosts are certainly great business for the city. Ghost tours are a nightly occurrence on the tourist trail, whether on foot, or by bus (have you seen the new black double-decker driven by a skeleton?).

Madness and marketing apart, ghosts play a part in the modern machine of life. They are the shadows that follow us, often acting as our conscience, guiding us in decision making, helping us keep on the right path.

In politics, ghosts abound (and the really ghoulish thing is that ex-politicians don't need to be dead to do the haunting).

Take Tony Blair - just when the Labour Party hoped he'd taken his designer suntan and Savile Row suits to some far away shore, he has returned to offer a partial apology for the Iraq War. For many, this is too little, too late.

The spectre of Blair is not the only "ghost" shadowing the Labour Party. Blairites were thoroughly beaten in the decisive leadership election which crowned left-winger Jeremy Corbyn. In choosing Corbyn, supporters have invoked the ghosts of Labour past - with Nye Bevan, the father of the NHS, cast as ghostmaster general.

Time will tell whether their trail takes Labour to Number 10 or into the political wilderness (once occupied by those other Labour souls, Michael Foot and Neil Kinnock).

The Tories have their own ghosts. The most obvious is Margaret Thatcher, unarguably their most successful post-war leader, who changed Britain in ways Cameron and Osborne can only dream of.

When they close their eyes at night and start thinking about their austerity agenda, does Maggie swoop into their dreams, hectoring them that There Is No Alternative?

You don't have to believe in ghosts to be thoroughly chilled by the cold and calculating justifications senior Tories have given for tax credits cuts, which are due to fall in December.

This time, it is the phantom of Thatcher's chancellor Geoffrey Howe that is making his presence felt. Tories freely admit that the current Chancellor is copying Howe's tactic of implementing the toughest cuts now, early in the parliament, banking on the public either forgetting or forgiving by the time the next election comes around in 2020.

Seeing ghosts may be a sign of madness, but the Tories must be truly crazy to think families struggling to earn a living on poverty wages will forget the Chancellor who took hundreds of pounds away from them. And at Christmas too.

If the Tories don't do a U-turn, Osborne will be cast as Ebenezer Scrooge.

And we know what the ghosts did to him.