Nissan Note ignition won't turn off after putting it into parking gear.

I noticed earlier today that it was difficult to put it into parking mode. Then tonight on getting home it went into parking mode but I couldn't get the ignition to make the final turn to turn off. I eventually gave up and the alarm made a lot of noise when I left it, then went quiet. I have called the Automobile Association, but they have a long wait list, so I'll be up half the night, waiting for them.