We have applied for PR in Singapore. I had worked in a British firm for 8years till 2009. If we mention that in our application, will Singapore government enquire or verify with that firm . Anybody applied for PR and had similar background ?

I applied PR 6 years ago and the ICA didn't verify with the company I was working in. However, I think it will be better for you to check with the ICA officer directly by calling hotlines. You should declare all information correctly like what Yuna mentioned.