David Cameron’s admission last night that he benefited from his father’s offshore investments – to the tune of tens of thousands of pounds – has forced him to promise to finally publish his full tax return, while it has also prompted calls for his resignation.

However, while the PM may have decided to come clean after days of scrutiny, there are still plenty of questions left unanswered. Here are five, for starters:

1. Why didn’t he provider answers earlier?

It’s not like Robert Peston was the first person to ask Cameron these questions – the fact Downing St published four separate denials by Wednesday show the PM has been feeling the heat all week. Only a few days ago, they were sticking to the line it was a “private matter”; now Cameron claims that he supports more tax transparency for prime ministers.

2. Why didn’t he register his interest in this offshore fund when he became an MP in 2001?

Again, Cameron’s failure to be upfront about the arrangement and how much he benefited from shows he knew the public perception would be appalling.

3. Did he dispose of any other shareholdings in advance of 2010?

Selling his shares in the Bahama-based investment firm just weeks before becoming PM – for £30,000 – has the look of a man trying to cleanse his past of anything embarrassing.

4. Has he used any other offshore investment vehicles as a way of generating income?

We only know about his interest in his father’s investment firm because of the Panama Papers leak. In his acceptance of a need for greater tax transparency for prime ministers he said he would happily publish his tax affairs “going back a couple of years”. His remarks surely raise more questions about his income before entering Number 10.

5. Did he dump his offshore shares because of the Lord Ashcroft non-dom scandal?

In the run-up to the 2010 election, around the time Cameron sold his shares, the Tories were facing questions over the then non-domiciled tax status of Lord Ashcroft, who was funding their campaign.

Relations between Ashcroft and Cameron have since soured, with Ashcroft claiming the Tory leader knew about his tax arrangements.

And if you want more proof that the two don’t get on…