Error creating resource: [message] fopen(): Unable to find the wrapper "https" on Ubuntu using Symfony

I am attempting to install Symfony3 on an Ubuntu 17.04 machine and am getting the error:

[GuzzleHttp\Ring\Exception\RingException]                                    
Error creating resource: [message] fopen(): Unable to find the wrapper "htt  
  ps" - did you forget to enable it when you configured PHP?                   
[file] phar:///usr/local/bin/symfony/vendor/guzzlehttp/ringphp/src/Client/S  
  treamHandler.php                                                             
[line] 406                                                                   
[message] fopen(https://get.symfony.com/symfony.version): failed to open st  
  ream: No such file or directory                                              
[file] phar:///usr/local/bin/symfony/vendor/guzzlehttp/ringphp/src/Client/S  
  treamHandler.php                                                             
[line] 406                                                                   
[message] Undefined variable: http_response_header                           
[file] phar:///usr/local/bin/symfony/vendor/guzzlehttp/ringphp/src/Client/S  
  treamHandler.php                                                             
[line] 407     

when running the symfony new command. I am running PHP version 7.19 and OpenSSL version 1.1.0f. I have also tried with OpenSSL version 1.0.2g (the version available from the Ubuntu package manager) and the same error occurs. I have also tried installing PHP from source using the --with-openssl[=DIR] flag pointing to the SSL directory in the untarred PHP source, but though this completes without error it doesn't help.

I have looked at answers like this:

Symfony 3 new project error

but they are all either for Windows (telling me to uncomment the .dll in php.ini which doesn't work on Ubuntu) or they are tell me to install a PHP 5 package, such as php53-opensll, which doesn't work on this system.

The output from phpinfo() includes:

OpenSSL support     disabled (install ext/openssl) 

In the Phar: PHP Archive support section, but I am not sure of the correct process to properly enable support in Phar, if this is indeed the problem area.

Any suggestions greatly appreciated.