Identify the most appropriate way of instantly restricting learners from accessing unwanted websites when using Internet during a lesson

1. Install a Web Filter: The first step is to install a web filter on the school's network. This software will block access to specific websites that are deemed inappropriate or not useful for the educational environment.

2. Customize the Filter: After installing the web filter, customize it according to the needs of the school. This usually involves creating a "blacklist" of websites that students should not be able to access. This list can be updated as needed.

3. Monitor Internet Usage: Regularly monitor the students' internet usage to ensure that the web filter is working effectively. This can be done through the web filter's reporting features, which can show which websites are being accessed and by whom.

4. Educate Students: It's also important to educate students about appropriate internet usage. This can be done through lessons, discussions, and the school's acceptable use policy.

5. Regular Updates: Regularly update the web filter software to ensure it's effective against new websites and techniques that may be used to bypass the filter.

6. Use a Secure and Private Network: Using a secure and private network for school internet access can also help to restrict access to unwanted websites. This can be achieved by using a Virtual Private Network (VPN) or similar technology.

7. Password Protection: Protect the settings of the web filter with a password to prevent tech-savvy students from changing the settings and gaining access to blocked websites.

By following these steps, you can effectively restrict learners from accessing unwanted websites during a lesson.