That's what this particular poll is showing. If it is true, then UKIP voters are returning to the Tories, perhaps in resignation.
As polls have margins of error, and in particular could underestimate support for (more) minor parties, then it's probable that UKIP support hasn't plummeted so much.
But any Tory "surge" has to come from somewhere. Ain't gonna be the SNP, and Labour support appears steady, leaving the Lib Dems (but they have already collapsed in support, probably) and UKIP.
As I've said earlier, for admittedly cynical reasons I hope that UKIP's vote share hasn't collapsed. We'll see if it stays strong in the actual poll. Svejk, you'll be pleased to see that a second poll reported in the same article shows UKIP support as strong as ever, at 15 +/- 3 %.