I think from time to time, these things happen.

When they happen, we have to make sure we deal with them and deal with them rigorously as well as transparently, and everybody can see that we are doing that.

And in that process, I think everybody should draw the right conclusions and do the right things, whether they are in the government, whether they are in the party or the public watching how we are dealing with it.

No system can be completely infallible.

You appoint people, sometimes things go wrong, you have to find out and you have to put it right. You have to find out yourself whether or not somebody tells you something is wrong and put it right.

I think we have had a series of high-profile issues recently.

I think in the Ridout case, the matter came up on the Internet.

The ministers went through a rigorous, full CPIB investigation, as well as investigation by SM Teo Chee Hean, and the results and the reports were presented fully in Parliament.

And even the Leader of the Opposition, Mr Pritam Singh, said nobody's alleging corruption or wrongdoing.

So, I think it is an example not of the PAP’s slipping standards but of how we deal with allegations against PAP MPs.

In Mr Iswaran’s case, the matter came up not from any external report, but because CPIB came across the issue while doing another investigation, and they told me, I said, take it up.

After a few months it came back to me, they said, there is something to this, we want to open a formal investigation.

I studied the paper, I said, yes, proceed, and that is what they have done, and it will go through to its full conclusion.

In the case of Tan Chuan-Jin and Cheng Li Hui, they did not live up to the standards which were expected.

We tried to get them to mend their ways, it did not work, and they had to go.

That is how the system has to function.

Sometimes things cluster up, but we make sure we put them right, and I hope I put them right and we will be able to set the right tone for a long time to come.

Because we are not just maintaining high standards for one election term or one generation of leaders.

You have to make sure that you can maintain this, sustain this, feel that sense of mission and responsibility, and be able to transmit that beyond your term into the next generation, and imbue the next generation of people who come forward to serve as well as people who grow up as mature Singapore citizens and voters to understand that this is how our system works, and this is how it has to work in order for Singapore to succeed.

One of the last almost public speeches which Mr Lee Kuan Yew made was when he had his 90th birthday and we gave him a party in Parliament. I mentioned this when I spoke at his memorial service.

He was very frail, he was in hospital, he came, and we were all gathered and there is a birthday cake, and he said only two or three sentences.

“Remember, never let the system go corrupt. Never, never let that happen. Uphold standards, make sure that Singapore can work.”

That is the key thing, and I am quite determined to do that and I am quite sure the 4G leaders are determined to do that too.