Explain why some british politicians thought it would be good for Great Britain to keep the colonies?

Which colonies?

Ontario,Quebec,Nova Scotia and New Brunswick

Read the section under Confederation.

http://en.wikipedia.org/wiki/Canada_under_British_rule#Act_of_Union_.281840.29

Some British politicians believed it was beneficial for Great Britain to keep its colonies for several reasons:

1. Economic Prosperity: The British Empire had a vast network of colonies that provided valuable resources such as minerals, agricultural products, and raw materials. These resources fueled Britain's industrial revolution and helped build its economic power. British politicians argued that maintaining control over the colonies would ensure a steady supply of resources and markets for British goods, leading to increased wealth and economic prosperity.

2. Military and Strategic Advantages: The colonies provided strategic military advantages for Great Britain. They offered crucial naval bases, control over trade routes, and acted as buffer zones between rival European powers. British politicians believed that maintaining control over these territories would strengthen Britain's security and global influence.

3. Global Power and Prestige: The British Empire was a symbol of British power and prestige. It was the largest empire in history, covering vast territories and multiple continents. Some politicians believed that retaining the colonies was vital to preserving Britain's status as a global superpower. They argued that losing colonies would weaken British influence and diminish its international standing.

4. Civilizing Mission: Many politicians embraced the ideology of "civilizing mission," which asserted that the British Empire had a duty to spread Western values, culture, and governance to less-developed regions. They believed that ruling over the colonies allowed Britain to impose law and order, bring education, infrastructure development, and modernize the local populations. This notion served as a justification for continuing British colonial rule.

To understand the specifics of why individual politicians supported the retention of colonies, it would be necessary to explore historical documents, speeches, and writings of those politicians to gain insights into their particular motivations, interests, and ideologies.